I mean just take the blackface thing. Let's say I want to go as Shaq for Halloween - I put on a bald cap because he's bald, and I put on some brown face paint because his skin is darker than mine. Where is the racism in acknowledging that African Americans typically have darker skin then Caucasians?
Or what if I want to do an impression of a Chinese person and I squint my eyes and talk in a Chinese accent and pronounce my R's as L's. Is it racist to acknowledge Chinese people have squintier eyes than caucasians on average? I mean there's a big industry in China to get "Westernized" eyes, even Jackie Chan did that shit. And the Chinese accent - it's just a fact that if you grow up speaking Chinese and then learn English, you sound a certain way. I'm sure we sound a certain way when speaking Chinese that's comical to the Chinese.
To me I see this as a lot different than enforcing harmful stereotypes that don't apply broadly across the board, like saying linking African Americans to crime, Muslims to terrorism, gays to annoying lisps, etc.
But acknowledging biological facts, like the relative smallness of Asian eyes, or the difference in colour between white and black people... is that so wrong?