Different people have different types of senses of humor. I was more disturbed by Steve Irwin harassing animals in their homes. Imagine how it would feel if some higher life form came to Earth and came into our homes to film us doing what we do, and got as up close and personal as Steve Irwin did. Granted he did a lot of good things for animal preservation, but every time I watched him I figured one day he'd get too close and either get hurt or killed.
Is Bill Maher wearing that costume and different than someone wearing a costume that makes it look like they've been attacked with a knife. People wear things like that all the time, but no one thinks about the fact that the guy waiting on you at the gas station on the way to the party you are going to dressed that way may have had a relative who was knifed to death. Why is it any different just because so many people admired Steve Irwin.
Because jokes about anyone dying just isn't funny? (To me at least) I don't care if it's him, that swimsuit model that just got killed by that reality tv whackjob, or someone in my town that I don't even know- I just don't think that it's funny. Just my opinion though, but I don't think that death is ever funny.