what would happen if I as a straight white (ish), male, rang the rozzers and reported (insert a minority group), for being racist or sexist - you would probably get charged for wasting police time. They might take a closer look at your finances, your social media comments, etc., anything to try and get something on you.
Here's another question: what would happen if a member of one minority group goes to the police with allegations of racism or sexism against a member of another minority group?