For me it was the weirdly simplistic tone that made it funny. I in no way suggest that rape prevention "blames the victim" and in my work with young girls I offer the usual with the disclaimer that in an ideal world this would not be necessary, but it is not a perfect world so for God's sake, keep yourself safe.
I've talked about this before at TN but it's been a long time ago - in a high school "respect" group I ran the girls were talking about how unjust it is that they can't walk in the park at night, and a boy, who I swear only joined the group to try to get laid, incredulously asked "you think I can walk alone in the park at night and not get jumped?" Which, fair enough. (He was actually an incredible addition to the group - a young Eminem among the female do-gooders.)
Anyway, it was a joke. That's all! Not a political statement. Jesus.