Good questions!
Let's start with the first:
Critical Race Theory is an ideal developed from Marxist theory that essentially asks human beings to see the world through a lens that sees people as either oppressed or oppressors based on their race and identity. This gets even more complicated when attempting to determine how oppressed one is - a factor determined by something called intersectionality. For example, if we are comparing three individuals - a black woman, a white man and a gay, black woman - the gay black woman is the most oppressed and the white man is the most oppressive.