It's always so funny when white people say "why do you make it about race?"
When the Supreme Court made segregation legal in Plessy v. Ferguson their justification was "Our constitution is colorblind and blacks think separate but equal is racist because they focus on race."
Anyways, she's not saying all whites who do soul/rap music (i.e Eminem, Adele, Duffy, Amy) are corny, but the ones who use it as a trend and don't really have much of an understanding of the culture outside of the fact that it's trendy (i.e Miley Cyrus, Iggy Azealia) are.