[sergiosgc]

The fact of the matter is that not telling racist jokes probably means you are racist. Mocking people for their faults is the most basic kind of humour. Stuff kids do in early school, to the point of being mean, and then scale back to socially acceptable levels. However, this is an humour class that never completely disappears. Whole comedian careers have been built on it (look at the TV show Seinfeld for an example).

When you actively avoid mocking someone because they have a visibly different skin tone, subconsciously you believe this is something they should be ashamed of. Racist, qed.

It is as ok to mock someone for being "african-american" as it is mocking someone for their closed Texan accent. And it is ok. Mock away, and take it in stride when it's your turn to be the target.