The problem with humor is that it gives license to personal attacks. If you are just being funny, just joking around, just having a little fun, suddenly it becomes okay to go to the gutter and tear apart another person.
You don't have to be correct. You don't have to be honest or truthful. After all, you're just joking, just having a little fun. Jokes aren't meant to be truthful, just funny.
Trouble is, they end up being hurtful, just the same. Humor gives license to hurtful. Bullying and harassment aren't normally considered good behavior, but if you fashion bullying and harassment into humor, many will say you are justified.
I think of Steven Colbert's rant against Donald Trump the other night. In the name of humor, he was about as derogatory as you can be against a president of the United States. (Oh, yes, others have surely been as derogatory towards the office, but you can only go so low, and at that point others can only join you as low-talking champs.)
No person should be subject to the treatment Colbert offered -- certainly not the president of the United States.