I think the problem with the term identity politics is that people have a very limited view of identity. Being white in America is apart of your identify, being gay is part of your identity, living in a big city is a part of your identity, being college educated is a a part of your identity. Each of these things and dozens more help to drive your political viewpoint and what you lobby for.
I think for the most part the political groups that have been branded as "identity politics" are all about fair treatment for all, these groups arise usually when fair treatment is not given to them specifically and so they lobby on their own behalf.
Look at Black Lives Matter, this is an organization / movement that sprung up after multiple killings of black men by police and is focused on police reform. You can call this identity politics if you want but then I would also say that Right to Life groups who protest abortion because of their Christian beliefs are also identity politics. So are PACs funded by wealthy individuals who would like to see their taxes cut. This is what I mean when I say all politics is identity politics.