I'm speaking for humans, and as a human, I'm telling you that you shouldn't be offended. Humans shouldn't be so touchy about other humans finding their foreign ways a bit comical. Some languages sound really funny to those who don't know the language. Why shouldn't they? The only thing that really stands out about Rosie's bit is that it was unimaginative.
But if I try to give myself some eye-folds to look Asian, is that so bad? Is there something wrong with having eyes like that that you don't want to be reminded of it? Who has made you ashamed of your race? Be proud. Hey, I don't know. Maybe that's easy for a white guy to say. There's a movement afoot to shame me of my ancestry, so maybe I do. I suppose my point is just that we can't get past race until we get past race. Rosie implied that the Chinese language sounds funny. Well, of course it does to a native speaker of English.
Suppose I start talking in an affected accent and some person of Hispanic persuasion overhears it. "Why are you making fun of Latinos?" he demands.
"Whatever do you mean?" says I.
"You know what I mean, you were talking in some stupid voice, trying to sound like a Latino!"
"Sir," say I, in high dudgeon, "do you mean to imply that Latinos sound stupid?"
"Wha-no-ya-you sound stupid trying to talk like a Latino!"
"Well, what makes you think I was trying to talk like a Latino? Is it because you think Latinos talk funny, and you thought I was talking funny? Sir, I perceive you are of Latino extraction yourself. As such, you should be highly offended by your deeply offensive remarks."
"Whatever."