Seems leftists may never learn that their hypocritical and insult-laden attacks only serve to drive out more of their own ranks and prove their critics right.

A New York University professor experienced “Twitter Hell on earth” after Fox News Channel’s “The O’Reilly Factor” tweeted out a podcast featuring his talk on the dangerous radicalism dominating college campuses.

My field trip to @FoxNews. See me seated in Bill O’@oreillyfactor‘s chair. pic.twitter.com/V6pIplteki — Michael Rectenwald (@antipcnyuprof) February 17, 2017

The backlash on social media to NYU’s Michael Rectenwald was not pretty.

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The illiberal left revealing its utter ugliness & hypocrisy. Is this how they treat everyone who appears on @FoxNews. Stalinist wannabes. — Michael Rectenwald (@antipcnyuprof) February 22, 2017

The professor is no stranger to “mean spirited” email as he noted he’s gotten his share from right-wingers.

“But now that I am a critic of the Left,” he wrote, “nothing from the past comes close to the kind of personal invective, baseless insults, vilely degrading language and imagery that I was barraged with from these Leftists — and all because I critiqued an IDEOLOGY and its mechanisms, and critiqued the hypocrisy of today’s illiberal leftists.”

Last October, Rectenwald made waves at NYU when he revealed he had an undercover Twitter profile, the “Deplorable NYU Prof,” which he used to call out the politically correct culture at college campuses.

Placed on paid leave following complaints by his colleagues, Rectenwald was then promoted by NYU in November from assistant professor to full professor, the New York Post had reported. His colleagues were also treated to a lecture from the dean about respecting opposing views.

But Rectenwald felt shunned after the incident and his treatment by leftists after the O’Reilly tweet sealed the deal for him.

“The Left has utterly and completely lost its way and I no longer want anything to do with it. I include most milieus of Marxism as well, as these have resorted to the same tactics in conjunction with the others,” he concluded in his Facebook post. “Good bye to all that. Good bye.”

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Rectenwald also shared the comments on Twitter where his handle is “@antipcnyuprof.”

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