Marc David Barnhill suggests that “intersectionality” is relevant to this issue, and I replied that in a way that’s another way of talking about mattering and the mattering map.
Some intersections are relatively trivial. Some places on the mattering map are very small, or picked out in frivolous colors. It’s possible to be very passionate about Star Trek or Shakespeare or hip hop or Emmylou Harris while still being perfectly willing to make alliances with people who hate the cultural products you love and love the ones you hate. It’s not just possible, it’s easy. Lots of categories are like that. They may be important for friendships, but they’re not important for alliances.
But when the issue is about equality – it’s different. People aren’t differentially treated according to whether or not they like Breaking Bad or Project Runway or the golf channel. (Broadly speaking. There are issues about culture as class marker, but not the way there were when every gentleman knew his Homer and he didn’t mean Homer Simpson.) People are differentially treated according to what sex and race and sexual orientation and class they are, among other things. That fact makes it much harder to forge alliances with people who want to treat others with contempt and people who dislike being treated that way. (That’s an over-simple schematic. People can dislike being treated with contempt while still wanting to treat others with contempt.)
So that’s why there are deep rifts.