'However, his guest, Kurt Schlichter, instead was determined to bring up President Bill Clinton’s affair with Monica Lewinsky. “…it’s gonna take a lot more for me to get upset at a woman who enabled a guy who turned the Oval Office into a frat house and his intern into a humidor,” he quipped.'
The topic was Trump and Clinton, not Bill Clinton.
Lemon was correct to end the segment if this nitwit refused to address the topic.
And before any ignorant rightwing loons start whining about 'freedom of speech,' the First Amendment concerns solely the relationship between government and those governed, not between or among private persons and organizations, such as a cable news channel and anyone being interviewed; where ending the interview in no way 'violated' free speech.