The Teamsters’ social media account attacked its own president on Wednesday, saying “unions gain nothing from endorsing the racist, misogynistic, and anti-trans politics of the far right,” two days after Sean O’Brien addressed the Republican national convention in Milwaukee.

O’Brien spoke at the convention on Monday night in Milwaukee, becoming the first leader of the union to appear at the convention in the union’s history.

O’Brien’s meeting with Donald Trump and his convention appearance have angered some Teamsters and others in the labor movement. Joe Biden has touted himself as the most pro-labor president in American history; Trump, in contrast, has been heavily criticized by unions for his administration’s anti-labor record. Anti-union groups have also criticized O’Brien’s appearance at the convention.

The union is facing a backlash from members and progressive groups over O’Brien’s appearance and the union’s consideration of abstaining from making an endorsement in the 2024 presidential election, including from the union’s social media manager.

In a now deleted tweet, the Teamsters posted a response to O’Brien retweeting an op-ed by the Republican senator Josh Hawley, in which O’Brien wrote: “Hawley is 100% on point.”

The deleted social media post said: “Unions gain nothing from endorsing the racist, misogynistic, and anti-trans politics of the far right, no matter how much people like Sen Hawley attempt to tether such bigotry to a cynical pro-labor message.

“The message this sends to Teamsters of color, Teamster women, and LGBTQ Teamsters is that they are not welcome in the union unless they surrender their identity to a new kind of anti-woke unionism. You don’t unite a diverse working class by scoffing at its diversity.”

“The message is clear – it doesn’t matter if you’re a Democrat, Republican, or Independent – the working class in America must be respected,” the Teamsters said in a post promoting O’Brien’s appearance at the convention.

O’Brien became president of the Teamsters in March 2022, after winning an election on being more aggressive in contract negotiations with UPS and new organizing efforts. The win came after James Hoffa, the son of Jimmy, had led the union the previous two decades.

Last year, in contract negotiations with UPS, O’Brien took a hardline approach, threatening to strike before reaching a deal ahead of the contract expiration. He also made headlines over arguments during appearances at Senate hearings with Republican senator Markwayne Mullin of Oklahoma.

During his speech at the RNC convention, O’Brien emphasized bipartisanship while criticizing systemic corruption and corporations.

“That’s why I’m here today. Because I refuse to keep doing the same things my predecessors did. Today the Teamsters are here to say we are not beholden to anyone or any party,” O’Brien said. “We will create an agenda and work with a bipartisan coalition, ready to accomplish something real for the American worker.”

Ahead of the convention appearance, the Teamsters have noted they are considering making no endorsement in the 2024 presidential election. The union has endorsed Democratic presidential nominees, including Biden in 2020, since making a non-endorsement during Bill Clinton’s re-election in 1996. The Teamsters endorsed Bill Clinton in 1992, but endorsed George Bush Sr in 1988 and Ronald Reagan in 1984.

“It’s certainly a possibility on O’Brien’s part. I’m not sure what the rest of the board would do,” said John Palmer, vice-president-at-large at Teamsters International. “I certainly will endorse whatever Democratic candidate emerges. I don’t know how many of the rest of the board would stand against O’Brien if he pushed a no endorsement.”

O’Brien rejected criticism of his appearance at the convention.

He said: “I don’t care about getting criticized. Its an honor to be the first Teamster in our 121-year history to address the Republican national convention. Think about this. The Teamsters are doing something correct if the extremes in both parties think I shouldn’t be on this stage,” he continued. “The Teamsters are not interested if you have a D, R, or I next to your name. We want to know one thing: what are you doing to help American workers.”

Other Teamsters members did not feel the same way, criticizing O’Brien’s appearance for providing support and publicity for politicians who have fought against workers’ rights.

The group, Bold Progressives, have started a petition urging the Teamsters not to stay neutral in the 2024 president election, asking members to sign on to the petition.

“It is misinformation for the Teamsters to stay neutral in 2024 if Trump and Republicans won’t publicly match the Democratic party’s strong pro-worker agenda – especially after Republicans have spent decades undermining workers and unions. No neutrality when Democrats are the clear pro-worker party,” the petition noted.

The group noted it has never petitioned a major labor union before.

“We have no objection to O’Brien speaking at the Republican convention. But he’s actively participating in 2024 misinformation by giving his stamp to Trump without calling on him to match the Democratic party’s strong pro-worker agenda,” the group said in announcing the petition.

“It’s even worse that he threatens to keep the Teamsters neutral in 2024, signaling that the parties are the same when he knows better.”