A controversial New York University professor returned from paid leave only two days ago and he is already back in the hot seat after Twitter deleted one of his tweets advocating free speech and railing against so-called social justice warriors (SJW).

Michael Rectenwald, who was put on paid leave last October following an uproar over a tweet criticizing the “liberal totalitarian costume surveillance” promoted by NYU resident advisers, saw a well-read tweet of his disappear from Twitter without any explanation from the social media company.

“It had to be someone within the Twitter administration,” Rectenwald told Fox News. “Instead of calling it social media, they should call it social justice media.”

Twitter did not respond to Fox News' request for comment.

Rectenwald’s tweet, which he says was his “most popular” tweet ever, targeted social justice warriors who he argues judge people by their identity rather than their ethics. The NYU professor has in the past fought heavily against trigger warning, safe spaces and bias hotline reporting on college campuses – arguing that they create “a culture of hypervigilance, self-surveillance and panopticism.”

One of Rectenwald’s Twitter followers tracked down a screenshot of the deleted tweet and over the weekend Rectenwald pinned a new tweet with that screenshot.

“Under SJW ideology ethics is transferred from the sphere of behavior to the sphere of IDENTITY. Identity determines ethical value under SJWs,” the tweet said.

Social justice warrior is a pejorative term for someone promoting socially progressive views such as feminism, multiculturalism and identity politics. It was first used as a term by activists to describe themselves, but has since been co-opted by critics of political correctness.

Rectenwald and other critics contend that SJWs are actually creating a less inclusive atmosphere on places like college campuses.

“People have no choice how they are born and they are condemned for it,” he said. “This is completely wrong.”

He added: “They claim they are liberal, but their ideas are illiberal through and through.”

Rectenwald said he is confused why Twitter would have taken down his post given that the company has been criticized in the past for allowing terrorist organizations to maintain social media accounts and because he believes his post was neither inflammatory nor derogatory.

“The comment is not disparaging to any individual person nor does it threaten anyone,” he said. “It’s just a critique of identity politics and SJWs that I’ve been arguing for a long time.”

Rectenwald is no stranger to social media controversy as his paid leave last semester indicates.

The liberal studies professor was put on paid leave after his Twitter comments under the name Deplorable NYU Prof provoked outrage among his colleagues on the Liberal Studies Diversity, Equity, and Inclusion Working Group.

“We fully support Professor Rectenwald’s right to speak his mind and we welcome civil discourse on the issues that concern him,” the group in a letter to NYU’s student newspaper, the Washington Square News. “But as long as he airs his views with so little appeal to evidence and civility, we must find him guilty of illogic and incivility in a community that predicates its work in great part on rational thought and the civil exchange of ideas.”

NYU stated that the leave was voluntary and had nothing to do with his tweets. Rectenwald, who has since changed his Twitter name from Deplorable to Deployable NYU Prof, also said he wasn’t mandated by the school to go on paid leave.