From homemakers and retirees to a billionaire real estate mogul, Americans who donate to President Donald Trump are facing an intense backlash — with some calling it harassment, and others saying it is simply an expression of national frustration.

Two high-profile controversies this week are fuelling a debate about campaign finance transparency in an increasingly divided America: The release of a list of otherwise-obscure donors by a Texas congressman, and the reporting of a big-ticket fundraiser by a wealthy Republican businessman.

"I think what you're seeing, especially from Democrats right now, is frustration at those who are said to be aiding and abetting this administration. And Democrats are looking for ways to express that frustration," said Democratic strategist Ian Russell.

First, Democratic Rep. Joaquin Castro tweeted out the names and occupations of 44 San Antonio residents who donated the maximum amount to Trump's re-election bid. It prompted swift accusations of "doxing," with Republicans charging that the high-profile call-out would invite violence and harassment against those on the list.

But Castro — the twin brother and campaign manager for Democratic presidential hopeful Julián Castro — said his post was "a lament" that so many in his majority-Hispanic hometown would give money to "a guy who's running ads talking about Hispanics invading this country."

He also pointed out that he didn't publish addresses or phone numbers, which, along with the names, is publicly available online through the Federal Election Commission (FEC).

My post was a lament - that so many people in my overwhelmingly Hispanic hometown would give large money to a President who is using it to target Hispanics as ‘invaders’. <br><br>No one was doxxed — no private address or phone <a href="https://twitter.com/hashtag/s?src=hash&ref_src=twsrc%5Etfw">#s</a> were shared. I’ve never engaged in that.<a href="https://twitter.com/Morning_Joe?ref_src=twsrc%5Etfw">@Morning_Joe</a> <a href="https://t.co/DgdX3wkJWI">pic.twitter.com/DgdX3wkJWI</a> —@JoaquinCastrotx

Arguing that Castro has a responsibility to protect the public as a member of Congress, White House adviser Kellyanne Conway said it didn't matter that the information was public.

"It matters that he's put some kind of target list and he's trying to make life miserable or worse for law-abiding citizens who are expressing their First Amendment right," she told Fox News.

A similar — but more targeted — donation furor also emerged this week when the Washington Post reported that billionaire Stephen Ross, CEO of Related Companies, would host a pricey fundraiser for Trump at his home in the Hamptons. It sparked calls for a boycott of upscale fitness clubs Equinox and SoulCycle, part of Ross's vast investment portfolio.

While he said he doesn't condone Castro's strategy, Russell argues wealthy donors have for too long thought that they could reap the rewards of political access without consequence.

"Trump has shown them that is a package deal. If you want the tax cut, you're along for the bigotry," he said.

Fellow Democratic strategist Craig Varoga agrees the rules of the campaign-financing game have changed since the arrival of Trump, saying donors can't selectively ignore what they're funding.

"You have the most divisive political figure in our recent history who is using all that money to run ads that are creating a climate of fear," he said. "You cannot be in denial about how that money is being spent and what that message is."

A political street fight

Experts say the fact that political donors are facing this kind of backlash is a sign of how divisive political discourse has become in the U.S.

"Increasingly, the current political moment has all of the calm restraint of a city riot, and incidents like these are akin to the street fights that break out on every block," said John Paul Rollert, a professor of behavioural science at the University of Chicago.

Social media supercharges boycott campaigns by giving people easy access to like-minded activists and effortless ways to express their anger, he said. And while boycotts may not hit a company's balance sheet, Rollert says businesses are aware of the potential damage to their image.

A note from our CEO <a href="https://t.co/UwxBWR76B0">pic.twitter.com/UwxBWR76B0</a> —@soulcycle

Bradley Smith, a former chairman of the Federal Election Commission, says elected officials shouldn't be encouraging people to harass and vilify others.

"We need to fight our political debates as discussions, as battles of ideas," he said, suggesting that voters instead express their outrage at the ballot box.

The transparency debate

Modern campaign donation disclosure laws were born out of the Watergate scandal of the '70s and the need for transparency and to hold officials to account, said Rick Hasen, an election law expert with the University of California, Irvine.

But the fallout from this week's twin episodes has raised questions around campaign financing transparency in an era where social media can quickly amplify just about anything. The result, some experts suggest, is that stricter limits should be considered on what information is made publicly available.

Current rules state that any donation over $200 must be made public. Hasen suggests that threshold should perhaps be raised to protect the privacy of people "who are very small players in this process." But he also said that claims of harassment resulting from the publicizing of donor lists have been exaggerated in the past.

Smith agrees, saying the disclosure law is intended to keep politicians accountable — and "not to help office-holders monitor voters and monitor people's political activity."

Democratic presidential candidate Julian Castro, right, and his twin brother Joaquin Castro are shown during a campaign appearance at a high school in Los Angeles. (Mario Tama/Getty Images)

Others worry that the debate around the weaponization of donor lists is a slippery slope that will harm transparency.

Sarah Bryner, a senior researcher with the Center for Responsive Politics, said the U.S. Supreme Court has upheld political donations as a protected form of speech, so that means donors must be held to account, too.

"I do agree there is a difference between targeting a person who owns a hardware shop, compared to someone who owns SoulCycle. That's an important distinction. But it's not something you can easily regulate," said Bryner.

While more battles over donor lists likely loom on the horizon ahead of the 2020 election, Bryner said she hopes it doesn't lead to a discussion about limiting disclosure, as that will ultimately harm transparency.

"It rests with the users of the data to be responsible with it and recognize that not everyone will use it for politically neutral purposes," she said.

How far does a boycott go?

On Fox News, some commentators dismissed the calls to boycott Equinox and SoulCycle as "virtue signalling," saying the faux-anger will be forgotten in a week.

With wealthy donors like Ross, many of whom oversee vast real estate and investment portfolios, questions arise about how far voters are willing to take their anger.

Will they extend their frustration to the shops and restaurants at the new massive Hudson Yards development in Manhattan? Will it affect attendance at New York Fashion Week? Or where people buy their coffee?

A woman walks past a SoulCycle studio in New York City. The billionaire owner of Equinox and SoulCycle, Stephen Ross, is holding a high-dollar fundraiser for Donald Trump, which has sparked calls for a boycott of his gyms on social media. (Drew Angerer/Getty Images)

For activists who track businesses linked to those who support Trump, some say a line must be drawn between the behaviour of the company and the individual who owns it.

Shannon Coulter, the founder of the #GrabYourWallet movement, which encourages consumers to stop shopping at places connected to Trump, says companies like Marvel are OK, because while Marvel Entertainment chairman Ike Perlmutter is a Trump donor and confidante, other branches of the company, like its film studio, promote diversity.

Likewise, the fact that tech billionaire and early Facebook investor Peter Thiel is a Trump supporter doesn't make the social media giant a target for activists, because the site is key to community organizing.

Coulter said she doesn't target small- or medium-sized businesses — but big players are fair game. She believes part of the SoulCycle backlash is because the company promotes messages of diversity and inclusion, which some see as running counter to Trump's rhetoric.

"I think that millionaires and billionaires are so insulated from the negative effects of Trump's extremism that they're a little bit out of touch with just how toxic his brand has become," she said.