Some intersections are oppressed by other intersections. Intersections are based on race, sex, gender, sexual preference, and many other divisions. Sanders is out because he's white, male, heterosexual, Jewish and old. He's an oppressor, whether he knows it, likes it, or not. A young, secular, gay, black woman is oppressed, whether she knows it or has ever experienced any oppression.
Mind you, it's not my thinking. It neo-Marxist, postmodern crapola escaping the universities and into the public square.
One of the most important distinguishing features is it is divisive. We can say MLK was about identity politics but of a sort that was inclusive, he wanted equal rights for blacks. The new identity politics is exclusive and aims to take power over and oppress those identity groups that at one time historically were possibly oppressors.