We laugh at racist and sexist jokes because it releases the tension held fast by idealism intolerant of imperfection. Fighting fascism with thought policing perpetuates the authoritarianism upon which the fascism is founded. Like gladiatorial sport did for Rome, politically incorrect comedy can vent primitive drives toward disorder.
The danger of edgy comedy normalizing bigotry used to be offset by the diversity of the crowd attending the same event. Comics in the 80s and early 90s could nonchalantly ask the audience, “How many of you are liberals? How about conservative?” and the crowd would respond without splitting into camps and booing the other. A joke was understood to be a joke and not a slippery slope into death camps or toxic-something culture. This mistrust of a vital venting opportunity for the other side becomes a self-fulfilling prophecy as accusations engender defensiveness and eventually preemptive offense.
Polarization will not go away with both sides becoming more authoritarian. As the disequilibrium mounts in culture, we need release valves, and I think acknowledging our prejudices with levity can loosen us up.
Further exploration
You Can't Hit Unsend: How A Social Media Scandal Unfolded At Harvard [npr.org]: Podcast episode about some students' racist and sexist jokes costing them their admission to Harvard, despite the fact that they were often making fun of their own class.
