Because it isn't possible that a white person means something different when saying something than a black person. Because in interview after interview with people practically begging her to admit that its all just the result of her upbringing, she has insisted, over and over again, that there is nothing wrong with what she has said, or done.
It's not the overblown PC police or loose cannon liberals who are doing this. It's the Food Network getting rid of a liability before she sticks her foot any further down her own throat. She made them millions. They're not going to give that up without reason. And she gave them plenty.