…as answered on Quora:
Liberals are not upset by Dave Chappelle. Leftists are; Progressives are.
Conservatives and other non-leftists have got stop bashing “liberals.” A liberal is for freedom of speech at the very least. It is a defining feature. If you give up on free speech, you give up on liberalism. You do not get to use the label. And leftists generally have given up the free speech cause. Today’s left-progressives sound like the conservatives of my youth, who thought it important to suppress disruptive and unsettling and non-nice speech.
Conservatives in the past were especially upset by frank or unruly speech about sex; today’s progressives are especially upset about frank or unruly or even just skeptical speech about “gender.”
And boy, does Dave Chappelle zero in on that obsession.
As for me, I have been a Chappelle fan since his “how old is fifteen really?” bit years ago. He is still provocative, funny.
It is just that now progressives have gotten so annoyingly anti-freedom and anti-fun that they cannot take a joke. They can dish it out, but cannot take it. Actually, it is worse than that: they have gone so far that they cannot really dish it out any longer. Jon Stewart was funny on The Daily Show and Stephen Colbert was funny on The Colbert Report. But Colbert is not funny any longer. Nor are the others in the late-night anti-Trump brigade. Why? Because they became relentlessly partisan and (worse) came to think of themselves as always right.
They are merely always left.
And hopelessly unfunny.
After I published this response, directly above, the original question was changed to reflect my complaint. It now reads “Why are the left so upset with Dave Chappelle? Are they only finding humor in bashing Trump and conservatives?” Which, because of grammar issues, may be worse!
Addendum 9/4/2019:
Wirkman Comment 
Dave Chappelle is the only comedian besides Tim Allen that dares to speak his mind.
Dave is hilarious & his humor bites those who believe Freedom of Speech is wrong.