racism is just an example of people's natural distrust of anything different from themselves. it is only an outward manifestation of our ignorance of how much the same all people are and, as such, it is harmless unless nurtured into hatred. this kind of distrust seems to be linked to some sort of survival instinct and, once the perceived difference is shown to be nonexistent, it fades away with understanding. by laughing at bigotry we are laughing at that part of ourselves that is wary of those we see as different and that laughter has a cleansing effect. if we can laugh at something then it doesn't seem so important and it is easier to dispose of.