I agree. Eminem did it, Elvis did it, there are many who have imitated black culture or characteristics for their own benefit, and to public acclaim. I don't think it is racist to take certain (obviously over the top and caricatured) characteristics and use them in a movie. I mean, is Chris Rock guilty of racism when he goes out of his way to caricature blacks? Or Chappell? Or Eddie Murphy?
It's a movie with two funny/annoying/comedic relief characters in it, not a statement about society today.