Too often, though, it's the offending party who tries to determine exactly what's offensive to subjugated groups. That conversation is always a disaster. Trying to convince a subjugated group not to feel a certain way about oppressive symbols – with decades or even centuries of history – is an exercise in hegemonic privilege:
Because I don't feel offended by it, you shouldn't either.
Basically, the desire to avoid hurt caused by an act of racial symbolism should outweigh someone's desire to make sure everybody gets that you're dressed as Barack Obama for Halloween. By continuing — every year without fail — to don blackface, brownface or slanted eyes, offenders are standing firm in their belief that they don't care: they don't care that they're hurting people, and they don't care that they're calling on centuries of hatred for a simple prop.
That's why we're here, with me writing about how blackface – a well established expression of prejudice and hate – is wrong. Halloween should be a night of fun and celebration, not a perpetuation of one of the most racially charged and offensive acts America has to offer. If you're just dying to use paint, maybe go as the Incredible Hulk instead.