I too am blond and used to be a bartender and the drunker the patrons got, the more need they had to tell me every dumb blond joke they ever heard (or even try to make up a few). I often laughed because the stereotype amuses me.

I do not believe that disability is funny but I can laugh at certain things. I work with a guy who has one leg. He has a great sense of humor and has never ever let it get to him. I bought him a shirt that said "I am only in it for the parking". He laughed so hard and couldn't wait to wear the darn thing. When he went to get his new license picture and renew his disabled parking permit, he wore the shirt. Made a few people at the DMV uncomfortable but a couple other diabled people in the office loved it. I guess when it comes to that there is a difference. Is someone laughing at them because they are different and deserved to be ridiculed or are they laughing at themselves because they don't take themselves too seriously.

Women who make sexist jokes amuse me because they are making jokes about the stereotypes which they obviously do not adhere to.