Stewart highlighted a clip from rising GOP star Ben Carson, who said last week that gays and "people who believe in bestiality" should not be allowed to change the longstanding definition of marriage.
"You get that one of those things is not like the other, right?" Stewart said. "It's like saying, 'I believe the law grants the same rights to all of us — whether we be Christians or rapists. It's nothing to do with anything."
Stewart also chided Republican Rep. Louie Gohmert, who recently equated limits on gun magazine capacity to gay marriage and bestiality.
"What is it with you people and the animal f—ing?!" Stewart said.
Watch the clip below, courtesy of Comedy Central: