I also should say, I don't expect everyone to have the same sense of humor. But folk do tend to come down hard on those who do have a dark/irreverent sense.
I would say if someone starts a thread on a serious subject and they don't want humor in it they should mention it in the first post and hopefully their wish might be respected, but on the other hand, it is a public forum, different pov's are what keeps things interesting.

really?..even if they had done the same to you, or worse when you were down?

I try not to direct my wrath at a person and point out that it is how I feel/my opinion. I may fail at it sometimes but I really am cool with people being who they want to be. I don't have to like it.