Is calling someone racist act of racism ?
How to stop racism, since discriminating racists for their beliefs is act of racism.

Recognition of racism, sexism, a or any other ism isn't the act of that ism. Anyone who says that is just someone desperately defending themselves. Those refuse to recognize these acts contribute to the problem.

That isn't to say, however, that some women who happen to be feminist aren't sexism against man, or African Americans who desire more than what white privilege allows in retribution... That's sexism and racism still.