Well, there is such a thing as casual racism, sexism, and homophobia, where someone who generally has no apparent negative feelings for a group will make a comment, usually in jest, which expresses racist, sexist, or homophobic sentiments. Now, many people have taken the position that casual discrimination is ok, as long as the intent is not to harm. This leads to many conflicts with two other types of people: 1) those who think casual discrimination doesn't exist, and that anyone who expresses discriminatory thoughts must be absolutely serious (these people are dumb, and don't understand nuance). 2) people who understand the difference between "real" discrimination and casual discrimination, and still don't like it.

Personally, I fall into the 2nd group. I think that bantering about with hurtful (or at least formally hurtful) speech only emphasizes our unwillingness to get over our collective xenophobia as a society, and influences us to still cling to subtle, subconcious discriminatory thoughts we don't want to have. Think of it like this: if your friend suggests going to KFC, and said friend happens to be black, do you really want the first thing that pops into your head to be the opportunity to make fun of your friend's race? Why are we so locked onto these predefined groups of people who instantly have a slew of jokes plastered to their backs just because of how they were born?

Besides all the preachyness, though, the whole "I'll tell discriminatory jokes, but its okay because I like the group I'm discriminating against" bit is getting old. There is still room for discrimination in comedy, but it should be good comedy, comedy that makes you think, and not just laugh. I still hear people telling racist jokes to each other, the kind that actual racists came up with, then everyone else started telling for shock value, sort of like dead baby jokes. But the weird thing:no one is even shocked anymore- everyone has heard these same jokes already ad nauseam- these conversations have devolved into contests of who has committed to memory the greatest number of insults to a substantial portion of the population. People aren't even trying to be funny anymore, they are just going through the motions of saying racist things, bonding over the fact that they still tell racist jokes even though they have long since stopped being funny.

So really, my case against casual racism is this one: it makes us worse people by desensitizing us to racism in general; if you are going to tell a racist joke, you can do better, especially if you can come up with something new; if you are going to joke about racism, you better be really good at it, and do it with a purpose, so leave it to the professionals.