I believe a large part is identity politics. A symptome is that a voter will agree with the policy of their preferred candidates, rather than choosing a candidate based on their preferred policy.
I'm implying this for both sides of the aisle.
I'm implying this for both sides of the aisle.
There are definitely people who use identity more than ideology to make decisions, and there are hypocrites, but it's not strictly useful to complain about them as if they are the only people in the discussion.