I'm not defending them, I'm questioning your (feigned?) outrage at them.  

And what is the difference? Someone makes a racist joke and another person is outraged. You say, what's the problem, it is all in good fun.

Why you would even lift a finger for someone that is purposely trying to pump themselves up by making fun of another group of human beings is astounting to me. The fact that you would sit by and question someone who is outraged by bigots makes it seem like you are defending the bigots.

The weird thing about bigotry and stereotyping is comes from ignorance of another group and rarely from experience. It spreads like brushfire amongst those who need to feel like they are somehow better or more important from those they put down.

As in this case, most don't even realize what they are doing and when called on it see it as trivial.

Adrian Piper a light skinned black artist did a performance piece meant to call attention to these kinds of trivial remarks. She would often find herself in a position where someone would make a racist joke not knowing that she was black. As a result she created a performance piece where, whenever a so called trivial remark was made she pulled out her calling card. It said:

"Dear Friend, I am black, I am sure you did not realize this when you made/laughed at/agreed with that racist remark." The card continues for several lines, concluding with the words, "I regret any discomfort my presence is causing you, just as I am sure you regret the discomfort your racism is causing me."