I recently advised a friend not to make a game similar to this one. Same idea based on the same event, but different in every other aspect. I think that it was a disturbing event and I don't believe people should make games or movies about it, but unless the artist displays the psychopath as a hero or god of some sort, there's nothing that can or should be done to stop these artists from expressing their point.
If you don't like the idea of the game, then don't play it. There is no reason to subject yourself to it if you don't like it. That would be like watching the news coverage of Anna Nicole Smith's death for the entire period of time that it was on, then complaining that it is all that is on. If you open your eyes there are plenty of other flashes on here that are equally or more insulting then this one.
I do appreciate you bringing to our attention that he is trying to make a profit over this. I think that he is making something that wasn't a big deal (in my opinion) into something that is wrong and that is disgusting. I only hope no one is actually contributing to his paypal account, in hope that he'll take the flash off.
If you know someone who is sitting inside, playing the game over and over again, have him/her committed.