Comedian Sarah Silverman may have told supporters of Bernie Sanders they were "being ridiculous," and should rally behind Hillary Clinton as the U.S. Democratic Party presidential nominee, but some of the "Bernie or bust" crowd is having none of that. And it could be largely because of a trade deal they just don't like. At the Democratic Party convention earlier this week, Alex White was holding a sign opposing the Trans-Pacific Partnership, an agreement he said will make life more difficult for his wife, who is suffering from a rare form of lung cancer. The Trans-Pacific Partnership has a "death sentence clause," he said, that gives drug companies a 20-year monopoly on prescriptions and will make some medications cost between $50,000 and $100,000 a year.

"That's why I joined the Bernie Sanders campaign because he's the only candidate that's been against the TPP from the very beginning. Hillary Clinton said it was the gold standard of trade agreements and shopped it around the world. So that's why I'm fighting it."

And that is the reason White — and some other Bernie Sanders supporters — have refused to heed the words of the Vermont senator and in the spirit of unity rally behind Clinton, the Democratic Party's presidential nominee.

"It's a deal breaker, absolutely," White said Tuesday at the convention in Philadelphia. "Everything we fought for in the Democratic platform is pretty much null and void if the TPP is enacted. It's a disastrous trade agreement. It's NAFTA on steroids."

Many of the disgruntled Sanders supporters say their opposition to the TPP deal has become a point of unification and has emerged as one of the significant reasons why they refuse to automatically throw their support behind Clinton.

'I'm never Hillary'

"I'm never Hillary," said Greg Phillips, an Indiana delegate, wearing a blue T-shirt with the logo "Ask me about Bernie" on the back, "I believe that she will say anything just to do what she wants. The biggest reason I can't vote for her is the TPP, she's going to pass that.

"So that's a huge part of why I can't even consider her as a candidate. So she's out."

David Berg said the movement from Day 1 has always been about 'all of us,' and never about one individual. (Meagan Fitzpatrick/CBC)

Sanders supporters believe the TPP, a 12-country multilateral trade agreement that has yet to be ratified, will lead to a loss of jobs, more outsourcing, drive down wages and threaten environmental protections.

Critics of Clinton have accused her of flip-flopping on the deal, initially supporting it but then opposing it just to curry favour with the political left of her party.

Earlier this month, Sanders was able to secure certain concessions from the party in the creation of its platform, a document he hailed as "the most progressive platform in the history of the Democratic Party."

But he failed to strike a deal that would see the party explicitly oppose the Trans-Pacific Partnership trade deal.

"It's one of the biggest issues and one of the biggest reasons why nobody here is Hillary supporters," Ernest Rondo said at a rally in support of Sanders earlier this week.

"None of us trust anything she says. That's the biggest thing. In fact, we believe the opposite thing will happen of what she says."

Convention suspends the rules, nominates Clinton by acclamation 1:44

That impression wasn't helped by Clinton's friend, Virginia Gov. Terry McAuliffe, who said on Tuesday that the nominee will ultimately support the agreement if she becomes president.

The Clinton campaign immediately rejected McAuliffe's comments but his words can only set back efforts by the Democratic National Committee to heal the party, rocked by the WikiLeaks release of thousands of embarrassing emails of senior party officials.

Those emails revealed that key party members favoured Clinton over Sanders as the presidential nominee and appeared to consider ways to discredit the Vermont senator during the primaries.

This has led to a concerted effort at the convention to placate outraged Sanders supporters, starting with the resignation of party chair Debbie Wasserman Schultz. And on Tuesday, during the nomination roll call, it was Sanders who was given the final words and who asked that all the delegates be allocated to Clinton.

But none of that has made any difference to some of his die-hard supporters, despite pleas from many Sanders backers who argue that refusing to vote for Clinton just helps Republican presidential nominee Donald Trump.

This is why comedian Sarah Silverman, during her prime-time appearance at the convention, told the Sanders holdouts — the "Bernie or bust" crowd — they were "being ridiculous."

Not about one individual

"This movement from Day 1 has always been about all of us, it has never been about one individual," said Utah delegate David Berg, who also firmly opposes the TPP trade deal.

Comedian Sarah Silverman speaks out to the 'Bernie or Bust' supporters 0:19

"Yes, we have been inspired, yes, we've been led by Bernie Sanders, yes, we love Bernie Sanders but we won't follow anyone blindly, including Bernie Sanders."

He said some of the delegates have been fighting to have a specific statement against the TPP included in the party platform.

"The TPP undermines democracy, it undermines workers, it undermines the environment," he said. "It's a bad deal all around and it needs to be stopped."

During roll call, Bernie Sanders asked that Hillary Clinton become the unanimous choice as the Democratic Party's presidential nominee. (Matt Rourke/Associated Press)

As for reaction to Silverman's chastising: "There is no question, Sarah Silverman is ridiculous," he said.

Zachary Edwards, from Louisiana agreed, saying it was "totally uncouth and out of order" for Silverman to denigrate the feelings of people who are "emotionally exhausted and expressing their outrage and anger over a rigged process."

"If we are going to differentiate ourselves from the Republicans and show the country that we are the better choice, if we're going to talk the talk, we have got to walk the walk."

And part of that is opposing TPP, which Edwards sees as a monumental issue.

"It's not necessarily a thing I see people keeping them from voting from her, it's the lack of transparency when it comes to the issue itself," he said. "There are 10,000 things I take into account when I decide who I am voting for, that's one of them."

But will he decide, in the end, to vote for Clinton come November?

"I have no comment," he said.