(CNN) Pete Buttigieg was getting a signal to wrap up his Iowa town hall, but he first gestured to the gathering of young people crouched near the stage as they clutched handmade signs.

"Do you want to go ahead and do the thing?" he asked them.

A few voices in the audience chuckled as Buttigieg invited the young activists, most of them college students at Grinnell College, to spread out so he could see their signs.

"Wall Street Pete," one sign read.

Another: "Youth to Pete: You will Kill Us."

"No, I won't! 'You will kill us?' That's really mean!" Buttigieg exclaimed. "I'm here to help you!"

The moment served as a window into the anxieties this young generation has about the inaction of older political leaders on major issues like the climate crisis -- and how much of that anger is now being trained squarely on Buttigieg, who, while their peer in age, has offered moderate views that often align him with older voters.

Increasingly, their opposition to Buttigieg is turning to fury, fueled by a boisterous online ecosystem of progressives who are driving anti-Buttigieg commentary and memes. They view him as beholden to corporate interests, unable to win over the diverse Democratic base that these activists take pride in, and disinterested in the systemic change they believe the country desperately needs on issues like the influence of big money on politics and climate change and systemic racism.

These narratives have persisted in spite of what his campaign points to as evidence to the contrary, including that Buttigieg has proposed plans to address those very issues such as a climate change plan to cut emissions to zero by 2050 and a proposal to address systemic racism that he calls the Douglass Plan.

Buttigieg supporters say the criticism has become unhinged, with some progressives eager to latch on to virtually any negative narrative about Buttigieg whether it is true or not.

There is no question: The youngest candidate in the 2020 presidential race, at age 37, isn't doing well with young Democratic voters. In the latest Quinnipiac poll , Buttigieg gets the support among just 2% of voters under 35. And in an average of CNN polling in October and November, Buttigieg gets slightly better with 8% of voters under 35 -- still a single-digit number.

While some in the Iowa crowd might have found Buttigieg's invitation to his protesters to be disarming, several of the students were not charmed.

"I thought it was condescending," said Dylan Bremner, 22, one of the students who protested Buttigieg over his plan to address climate change. "When he said 'That's mean,' I think it's pretty f***ing mean that you're not going to save us."

"I didn't feel like he was very clear and candid," said another student, 20-year-old Oscar Buchanan.

Since he jumped into the race, Buttigieg has gone from a little-known, small-town mayor, to representative of the Democratic Party vision has of itself as an inclusive party to, now, the arch-nemesis of certain progressive advocates.

The intense heat on Buttigieg from some corners of his party comes as he rises in both early state and national polls and vies with Massachusetts Sen. Elizabeth Warren for a slice of the college-educated electorate. Both candidates have upped their contrasts with each other in recent weeks as the Iowa caucuses near.

"The nature of presidential politics is the better you do, the more you are tested," said David Axelrod, a former senior adviser to President Barack Obama and chief strategist of his campaigns. "Buttigieg has made a pretty remarkable progress in 2019. Now he is being tested as a legitimate top tier candidate and we'll see how he handles it."

"It is an inevitable part of this process," he added.

#NeverPete

Buttigieg's critics cite a dramatic turn in his approach to his candidacy and are particularly incensed by his criticism of Warren on "Medicare For All." (Buttigieg, for his part, has pushed for a proposal called "Medicare for all who want it," an option that would keep private health care plans.) They consider his low standing with black and Hispanic voters to be disqualifying, and pejoratively refer to him as "Mayo Pete" for his overwhelmingly white supporters. As a result, his candidacy, in their view, is akin to the vanity project of an overly ambitious, privileged white man.

Some even readily share a "NeverPete" hashtag at the mention of his name online, reminiscent of the "Never Trump" Republicans who commiserated in opposition to Donald Trump's candidacy during the 2016 election.

"He's phony," said Adam Jentleson, when asked why he opposes Buttigieg's candidacy so strongly.

For Washington insiders, Jentleson is a well-known figure, a former senior aide to former Senate Democratic Leader Harry Reid, a far cry from the kind of left-wing progressive candidate Jentleson now would prefer. But now, Jentleson is known online as a progressive flame thrower, leading the anti-Buttigieg charge and slamming him for his attacks on more progressive candidates like Vermont Sen. Bernie Sanders and Warren.

"I was supportive of him on Twitter and stuff, but then he took a hard turn," explained Jentleson, who has also become a vocal Warren defender. "He's been validating Republican lines of attack consistently in ways that, if Warren and Bernie were the nominee, will give Trump a lot of footage to use in ads against them."

Online, criticism of Buttigieg seems to be snowballing from questioning his moderation to suggesting that he is a Trojan Horse. His harshest critics pin him with the worst of descriptors, including one recently who called him "racist, arrogant, dangerous, a warmonger and not qualified to be president."

Buttigieg's campaign largely dismisses the intense criticism they have experienced from people like Jentleson. "We're not focused on the small echo chamber of Washington insiders talking to each other on Twitter," said Chris Meagher, a Buttigieg spokesman, "we're focused on talking to voters about the issues that matter most to voters." He continued: "This election is about defeating Donald Trump and uniting the country the day after this president leaves office. Pete is the best candidate to do just that." But the contempt that has played out online has also started to playout offline, as evidenced by protestors at the Grinnell rally.

A new wave of protests

The controversy over his time at McKinsey as a management consultant has fueled accusations that he is bought and paid for by corporate interests. And opposition research has flourished online, including one that accused him of playing a role in a bread price fixing scheme at a Canadian grocery store chain that began and ended long after his months-long consulting stint for the company. The chain, Loblaws, released a statement saying Buttigieg had nothing to do with the scheme.

The kind of attacks that have been directed at Buttigieg have puzzled the candidate as well as his aides. And as they have gone from the internet to real life, including a wave of new protests outside of his high dollar fundraisers.

"It is a little strange, because I think that I broadly share a lot of the same values and goals," Buttigieg told The Washington Post's Bob Costa in an interview when asked if the protests bother him. "It's a little hard to have a conversation with them, so I don't know for sure."

Buttigieg senior adviser and communications director Lis Smith is often on the front lines of batting down what she calls "bad faith" attacks against Buttigieg on social media.

"It's bizarre given that Pete is the literal polar opposite of Trump- in words, deeds, values, experience, demeanor- but he melts people's brains in the same way and completely blocks out the sun for competitors similarly," she tweeted this month.

It has been perplexing to Buttigieg supporters that a particularly vitriolic brand of anger has been reserved for Buttigieg rather than other moderate candidates like Minnesota Sen. Amy Klobuchar and former Vice President Joe Biden, both of whom share Buttigieg's positions broadly on issues like Medicare for All and college affordability.

Many of the progressive voices fanning the anti-Buttigieg flames explain the disproportionate attention by pointing to Buttigieg's standing in the polls and a feeling of inevitability that Biden's candidacy is not as strong as it currently seems.

Buttigieg and Biden: 'Two generational ends of the same problem'

The "brain-melting" power of Buttigieg might also be attributable to the very thing that he touts as an asset: his age.

Buttigieg has pitched himself as the candidate of a younger generation. But among some people in that generation, his current political positioning has filled them first with disappointment, then with rage.

"He tried to fashion himself as someone more progressive on the outset and is now caving," said Jordan Uhl, 32, a progressive organizer who has been a vocal anti-Buttigieg voice. "You could say similar things about Biden, but Pete is much more brazen about it."

"Biden has a much longer history in public service and that's what leads people to not latch on to the same attacks as Pete," he added.

Uhl cited former President Barack Obama as an example of a candidate who represented generational change and who he characterized as a crusader for systemic change to the political system.

But presented with the argument that some of Obama's policies would be considered more moderate than Buttigieg's in today's Democratic Party, Uhl paused.

"The thing is Obama was willing to speak to systemic issues and a lot of younger people are becoming increasingly disillusioned and cynical because time and time again candidates would pay lip service and not do it," he said. "Pete's not even trying."

And then there are the the hard-to-define ways in which Buttigieg seems to grate against some Democrats' nerves, even the ones who might be expected to be drawn to his candidacy the most.

The distaste among some gay Democrats to Buttigieg has been the subject of a fair amount of analysis -- even raising the interest of Tim Miller, a moderate gay Republican and former Romney aide who has quizzically observed what he believes is a disproportionate amount of vitriol directed toward Buttigieg.

"They're the meanest," Miller said. "Within the gay community, unfortunately, I think it's a lot of resentment that Pete does not represent the gay ideal -- the pre-conceived notions about what a gay President would act like."

"The idea that he's a closet Republican is absurd, but I think because of his nature as a mild-mannered, traditional-acting religious man, that it's easier to demean him as being Republican lite," he added.

But for others, the part of Buttigieg's identity that is the most salient is not that he is gay, but that he is white, which they believe has insulated him from the kind of scrutiny that other candidates have been subjected to.

"I think Buttigieg and Biden are two generational ends of the same problem," said Jodi Jacobson, a progressive advocate who has taken issue with Buttigieg. "They're both white guys they both get away with saying stuff that we wouldn't abide by other people."

Throughout the Trump presidency Democrats have insisted that removing him from office is a top priority, but the #neverPete sentiment is testing that.

Asked whether he would vote for Buttigieg if he were the nominee, Uhl wouldn't say.

"I don't know," he replied. "On a theoretical level, you're under no obligation to vote. Not voting is as important to consider as a speech mechanisms as voting."

Bremner, the senior at Grinnell College, bristled at the question.

"I dislike when people ask me this question," he said. "The Democratic Party needs to take seriously whether it wants to get the support of young people."

"They're completely ignoring us and they still expect us to vote for their corporate candidates?" he asked.

But even for some of Buttigieg's critics like Adam Green, co-founder of the Progressive Change Campaign Committee, not voting for whoever is the nominee goes too far.

"Everyone should vote," said Green. "(People can decide) how many times they want to volunteer or how much they want to donate, but it is moronic not to vote against Trump."

This story has been updated with additional comment from the Buttigieg campaign.