[Wildcat!]

Its a comedy routine! And its an accepted joke. The OP is probably right saying it it wouldnt be well received here. NOt because peolpe are somehow more tolerant, but because there is more tension between the two races, than there is over there. Hence the example of what someone close to you can get away with, and a stranger cant. In the UK, the black person is more of a stranger than he is in the US.

For example, the blac dude in the US, have a lot more close white frinds, that would make such a joke in real life. Where the black in the UK generally doesnt.