The accounts cite Mostofsky’s registration as a Democrat in making the case that he is associated with Antifa, the loosely organized leftist anti-fascist group that right-wing media has sought to blame for the Capitol violence.
The FBI has found no evidence of Antifa involvement in the mob, but the idea has taken root in many right-wing circles.
In a Twitter thread Thursday, conservative journalist Alexander Muse, who has 77,000 followers, claimed that Mostofsky was a Biden supporter and insinuated that he might be involved in Antifa. He also claimed that Mostofsky is a Joe Biden supporter, retweeting an Associated Press story that states that Mostofsky is a registered Democrat.
But in New York City, where registered Democrats outnumber Republicans by nearly seven to one and most general elections are decided in Democratic primaries, many conservatives register as Democrats so they can vote in primaries. Mostofsky lives in Brooklyn.
“Left-wing activists like Aaron Mostofsky and his friend see all Republicans as ‘cavemen’ and ‘white supremacists’ and that guided their choice of outfits for their adventure. It is not clear if Aaron or his friend are active within the Antifa community,” Muse wrote.
The claim that Mostofsky was a left-wing agitator has circulated widely. Kyle Becker, a conservative journalist with over 150,000 followers, retweeted one of Muse’s tweets about Mostofsky, which was then retweeted by Donald Trump Jr, who has 6.5 million followers.
The claim even made it into the social media posts of a pro-Trump Orthodox Jewish influencer, Michal Weinstein, who shared a part of Muse’s Twitter thread with her Telegram channel. (Weinstein recently started posting on Telegram instead of Instagram after a social media crackdown on misinformation that targeted Donald Trump as well as other Trump supporters.)