If leftists want affirmative action, why are they so hostile to whites who believe it's unfair and racist ?

Affirmative action has mostly been done away with. It has been replaced by Equal Employment Opportunities.  Schools also must now consider many other factors in admission, diversity itself plays a very minor role. This was the latest Supreme Court Ruling.  

Connor, I’ve been seeing you here for a bit. I’ve noticed you lack critical thinking skills. You aren’t very intelligent and that’s ok. Connor, what you need is to do some research on Google and to distance yourself from any news TV. I doubt humanity when people like you come to ask boards and ask questions like this. I am not even going to entertain this question, Connor.

Because almost always such a belief is based on distortion and mischaracterization -- usually deliberate. 

Why are racist Whites so against it when it's been White women who benefited from it the most? Misogynist, too I guess.

Uh are you stupid or just trying to be a troll and failing miserably?