I hate the phrase "identity politics" almost as much as I hate "political correctness." Both are invented phrases that are increasingly used by people to justify their prejudice and hate.
It's particularly ridiculous because all politics are about identity. In fact, it's not a stretch to say all of life is. Our identity - how we define ourselves - and the groups we are part of as a result, are integral to our psychological wellbeing, and social functioning.
Human beings are herd animals, and we naturally form groups, whether that be tribes, communities, work teams, or as followers of particular rugby teams.
We generally see people in groups we are a part of as more trustworthy, more honest and more likeable, and people in groups we aren't part of as the opposite. This is basic social psychology: the in-group/ out-group phenomenon.
But in-group identification isn't so strong that we can't overcome it. Looking for similarities tends to help, as does understanding and allowing ourselves to get past stereotypes via real world experience of people we experience as "different".