I am not a sexist, but I still find myself laughing at sexist humor. Is that wrong? The answer is... no. Take the exchange that is located at the bottom of this post as an example. It's funny because of Stan is a complete idiot - not because that he is trying to insult Francine. Justification... I think so.
Francine: Stan, we've been wondering around for hours. Klaus' bowl is starting to freeze. It must be ten below out here.
Stan: Fine, if you hate Christmas so much, you can go wait in the car.
Francine: So what are you going to do, spend all night looking for the perfect tree? You'll catch your death out here.
Stan: Honey, just because snow is the same color as our refrigerator doesn't mean you know how it works.