A women's rights activist who got into an argument with an attendee at Lia Thomas' competition over her gender said there was a sinister move on the left that was prohibiting speech about women. 

"Women are called cervix-havers, menstruators, chest feeders, birthing persons. So we have to give up the language that describes us. … The only people that are allowed to be called women these days are actually men," Kellie-Jay Keen said on "Tucker Carlson Tonight" Thursday. 

"The person in front of me was quite happy to say that [Lia Thomas] was definitely a woman," she said. 

WOMEN'S ADVOCACY GROUPS SILENT ON TRANSGENDER SWIMMER LIA THOMAS' DOMINATION AT NCAA CHAMPIONSHIPS

Pennsylvania's Lia Thomas transgender swimmer NCAA champion

Lia Thomas wins the Women's NCAA 500 meter freestyle swimming championship, March 17, 2022, in at Georgia Tech in Atlanta. (AP Photo/John Bazemore)

Thomas, a University of Pennsylvania student, won the NCAA women's 500m freestyle title on March 17. 

"Why aren't people who say they have the interests of women at heart standing up and saying, no, you can't pretend that being a woman is as simple as changing your clothes?," host Tucker Carlson asked. 

"I've thought about long and hard. I think it comes to cowardice. I think it comes to a cult-like mentality. I think these people are brainwashed. They are experiencing truckloads of cognitive dissonance. I talk to many girls outside the swimming pool [at the competition and asked] ‘what is a woman?’ And they literally would not speak. It's really sinister," she said. 

Kellie-Jay Keen Lia thomas transgender swimmer NCAA champion

Women's rights activist Kellie-Jay Keen and Lia Thomas (Fox News | Hunter Martin/Getty Images)

Tucker added that the movement supporting transgender women to compete in female sports is "bullying"

He asked, "Did anybody at the meet say, Wait a second, that's cheating. This man is cheating because that's what it is."

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"I don't think anyone dared say it ... There was just this oppressive silence on. Everybody knew that there was a man in the pool racing with the girls. Everybody knew it. And those that knew it wouldn't say it."

"So it's just really scary. This is why … it's fantastic that you talk about this quite a lot, Tucker, because so many other broadcasters are simply too afraid."