Sexism - "prejudice, stereotyping, or discrimination, typically against women, on the basis of sex."

Now even the definition agrees it usually applies to women, that's fair. However it doesn't mean that women don't sometimes stereotype or hate men.

Racism - "prejudice, discrimination, or antagonism directed against someone of a different race based on the belief that one's own race is superior."

There is lots of prejudice against white people as against black people, there is also lots of antagonism.

I don't know why you think our mammalian instinct to prefer in group against out group only applies to white people. Honestly, it is absurd.