Problematic stuff. As E.B. White observed, it's possible to analyze a joke. It's like dissecting a frog, though: the subject dies. Humor can be thoughtful, or angry, or ( as any schoolyard child can tell you),terribly wounding.It all depends on intention and trust.Since my friend is not trying to hurt me by telling this joke, she or he must be expressing some sort of trust or understanding. Can bad jokes encourage bigotry? They can if a bigot needs encouragement. On th other hand, the question,why would this person assume I would find this funny? can be an interesting lesson all by itself.