Apparently it's called post ironic humour.
I must have slept in the day it became acceptable for a w hite man to dress up in a fat suit and black up his face and say "oh baby" for it to be funny.
Catherine Tate did sketch were she looked at at Asian man and said "bud bud bud". Hilarious!<<Now that's irony.
The difference you're looking for is class, if you are middle class or went to University then you're post ironic, if you did'nt then you're an ignorant racist bigot.