Both parties try to be all things to all people, so the Republican party tries to show itself as accepting to the “good” gays etc., and the Democratics have kept the Hyde Amendment so the more pro life people can be all like, “At least my money isn’t being used for it”.

I think people also vote in line with their family and friends and may have just been supporting a party their whole life so as either the party or the person changes, they just keep voting that way.