Louis C.K. faced sharp criticism Monday after audio surfaced online of a stand-up routine in which he mocked survivors of the school massacre in Parkland, Florida, as well as people who identify as nonbinary.

The Emmy-winning comedian, known for his brand of dark humor and crude jokes, has largely avoided the limelight after admitting more than a year ago to sexual misconduct.

But he has continued to appear in small clubs in recent months. The leaked audio, which was posted to YouTube on Sunday and later deleted, was taken at the Governor's Comedy Club on Long Island, New York, the venue's owner confirmed to NBC News.

"Louis did six shows for me in about eight or nine days," James Dolce, the owner, said. "Every performance was left with standing O's."

In a two-minute clip that was shared on social media, the 51-year-old comedian addressed the younger generation and the need for acting politically correct.

In discussing people who don't conform to a gender, "they're like royalty," Louis C.K. said. "They tell you what to call them. 'You should address me as they/them, because I identify as gender-neutral.' Oh, OK. You should address me as 'there' because I identify as a location."

Then, he appeared to talk about last February's mass shooting at Marjory Stoneman Douglas High School in Parkland, where 17 people were killed and 14 others wounded.

"They testify in front of Congress, these kids? What are they doing?" he said. "You're young, you should be crazy, you should be unhinged, not in a suit … you're not interesting. Because you went to a high school where kids got shot? Why does that mean I have to listen to you? … You didn't get shot, you pushed some fat kid in the way, and now I've got to listen to you talking?"

Dolce said he continues to have an open-door policy with Louis C.K.

"The guy's a comedy genius and always has been. He can talk about whatever he wants to talk about," he said, adding that he didn't notice any negative reaction from the crowd. He also said the people who came to the shows at his club knew they were going to see Louis C.K.

"Some things can be taken out of context and sound different than when you're listening to the entire set and you get the full understanding," Dolce said.

But Fred Guttenberg, whose daughter Jaime was killed and son survived the shooting at Parkland, tweeted Monday that he couldn't find humor in what was said.

"To anyone who knows Louis CK, please deliver this message for me. My daughter was killed in the Parkland shooting. My son ran from the bullets. My wife and I deal with loss everyday," Guttenberg wrote. "Why don't you come to my house and try out your new pathetic jokes?"

LEAVE LOUIS CK IN 2018. WE’RE NOT TAKING THIS ENERGY INTO 2019. thank u. — Delaney Tarr (@delaneytarr) December 31, 2018

Hey Louis CK - since you like making fun of me and other Parkland survivors behind closed doors, I’m right here if you want to talk. Just try to keep it in your pants, ok? — Aalayah Eastmond (@AalayahEastmond) December 31, 2018

Louis C.K, although taking jello shots & eating mushrooms might have been ideal for you when you were 18, that is not the luxury that we have after having to see our friends and classmates in caskets because of preventable gun violence. https://t.co/Hx5cGoxOPn — Kyra Parrow (@longlivekcx) December 31, 2018

The set was also criticized by other comedians and entertainers on social media.

"You know what's the worst, most boring kind of comedy? The kind where older white men are angry that older white men can't do or say whatever the [expletive] they want anymore," tweeted Andy Richter.

"This hacky, unfunny, shallow routine is just a symptom of how people are afraid to feel empathy," director Judd Apatow also tweeted. "It's much easier to laugh at our most vulnerable than to look at their pain directly & show them love and concern. Louis CK is all fear and bitterness now. He can't look inward."

I think it would have been a story two years ago because when he talks about the fat kid who got pushed in the way he seems to be implying the kids who fight gun violence survived because they sacrificed other kids.That is horrific at any time. He has kids. Where is his heart? https://t.co/MayDQM4hFv — Judd Apatow (@JuddApatow) December 31, 2018

Louis C.K.'s career was upended after an exposé in The New York Times in November 2017 in which five women accused him of sexual misconduct, including masturbating during phone calls, dating back at least 15 years. In the wake of the allegations, screenings of his latest film were canceled and a second special on Netflix was scrapped.

He later responded in a statement that "these stories are true," and that "I have been remorseful of my actions." He added that he wanted to "step back and take a long time to listen."

After lying low in the months that followed, his more recent return to the stage received mixed reviews from those in the entertainment industry who felt his comeback was premature. A call to his former spokesperson was not immediately returned on Monday.

Adding to the controversy, a 2011 HBO special in which Louis C.K. said the N-word also triggered criticism after it resurfaced this month on social media.