UPDATE/FURTHER READING: I wrote a more in-depth piece on this here that also links to some fantastic commentary from other voices.
And make no mistake, these costumes are racist. Even if you don't think they are. Even if I'm just being a big oversensitive PC baby. Even if your counterarguments to all of this are well-reasoned, you're still on the "uncreative jackass" side of this debate.
And that's what this comes down to, in the end. These costumes aren't just offensive and oppressive, they're really boring too. I mean, if you have one night to dress up like something--anything-- that you're not, and the best you could think of is "Jamaican guy" or "Mexican," that's pretty sad.
So this Halloween, forget the sombreros, feather headdresses, turbans, kimonos and (ugh) blackface makeup. Be a robot instead. Be a vampire. Bake some muffins and be the goddamn muffin man. Or just stay home and eat candy. Isn't that what Halloween is all about anyway?