Religion, in fact, has always been a hot-button topic for satirists. To some people, faith is faith and anything that questions their church's teachings or pokes fun at them amounts to blasphemy, even heresy. Thus, Monty Python inspired large organized protests with Monty Python's Life of Brian because its pointy-edged comedy suggested that in the time of Jesus there might have been other people who were mistaken as messiahs, both willingly or unwillingly. Indeed, Python's jokes are aimed more at conventions of religious movies, particularly the pompous portrayals of the Romans in all those 1950s' Bible epics. No such pretensions for Michael Palin's Caesar, who speaks with a speech impediment and doesn't understand why everyone thinks it's funny that one of the guards is named Biggus Dickus.
Race is also a taboo that can lend itself to brassy, outspoken humor.
Joking about race, even in a smart way, remains a sure way to provoke misunderstanding and draw offense, as Warren Beatty found out with Bulworth , the film that seems to have propelled him into the presidential race. His nervous breakdown was the perfect metaphor for race relations. Violent films have created an us vs. them mentality in the Hollywood-Washington community and comedies that lampoon violence inevitably get lumped in. But other films giggle at that queasy sense of reality and do so with a lot more laughs than Stone's. Think of the shocked laughter when John Travolta accidentally blows the guy's head off in Pulp Fiction or of the Black Knight in Monty Python and the Holy Grail who tries to fight on, even though both his arms have been hacked off and are merely blood-spurting stumps.