When confronted with blah blah about your social justice class, just refuse to participate. There is no functional necessity in the subject so "I'm not white." from a lily white nerd completely upsets their apple cart. What are they going to say, "Yes you are?" By what standard? Will they admit up front that they're judging another person by the most racist standard of all? Don't offer an explanation, you don't need to. Just refute everything you don't like the implications of. You don't even have to be coherent, but by all means, never justify anything.
Then for dessert, go to the school board meeting and start your statement with, "As a minority black woman..." Make the Beast swallow it's own tail