An airplane loses one of its engines and starts to lose altitude

Since they're flying over the ocean, all the nearest airports are hours away, so the pilot says:

'Ladies and gentlemen! Unfortunately, we'll crash... unless we get rid of some extra weight. The stewardesses have already thrown out all unnecessary objects, but this wasn't enough, so a few passangers will have to sacrifice themselves as well. Are there any volunteers?'

Dead silence.

'Then, we'll have to choose based on a certain quality,' continues the pilot. 'Of course, we'd like to avoid any semblance of racism, so we'll go in alphabetical order. Please, all African-Americans stand!'

Nobody stands up.

'Then I'd like to ask the black- and brown-skinned passangers to stand up!'

At this point, a black boy whispers something to his father:

'Dad! I always thought we were African-Americans. And our skin is black too, so why didn't we stand up?'

'Shut your mouth, son,' says the father. 'Here and now, we're niggers!'