That does seem to apply across the board. You can make jokes about your own ethnicity, for example. Of course, it usually helps that they are funnier than the Bernard Manning type.

Today at the bus stop there were two guys gleefully exchanging racial slurs for fun. The black guy was getting the upper hand, the white guy said it was clearly because his brain worked better in this heat, and so forth. It was lovely. They were having fun. It was rather lovely.