There are a large number of people that have a soul based connection to a political party. What do I mean by that? You are, at your core, a spirit. You have a soul (not the same thing) and you live in a body. The soul is your intellect, will, and emotions. Satan operates by manipulating people's souls, usually their emotions. Many people form a connection to a political party or movement based purely on that and will just completely ignore facts that contradict their allegiance.

My grandfather was a righteous man in nearly every way. Very much a conservative in his thinking and the way he lived. Yet he always voted Democrat because of his remembrance of FDR.

Union people vote democrat for these kinds of reasons. Minorities vote dem for these kinds of reasons. Very few people buy into the actual party platforms and most really don't want to vote but they're constantly told it's their duty so they trudge off to the polls and complain then vote based on feelings.