Many here are offended when they read things they would rather not read, because it goes against their moral values and convictions. Evidently, when someone gets a sensitive nerve touched, is not funny. But they still rate the review as funny just to make themselves feel better and less guilty. Incidentally, they despise an action or attitude they themselves are practicing. After all, he who stands for nothing, will fall for anything.
Update: see what I mean. I was dead serious in my review, yet it took only 35 seconds to get not one but two funny votes.