Well, to extend some grace, most of those whom you describe look at politics and elections the same exact way they do a sporting event. It's a contest and they want to be on the "winning team" just to feel the "euphoria" of a win and all the parades and parties that happen afterward so they can say "I was there. I had a part in the big win".
For the majority - principles do not exist except when it is convenient.
The only principles for most is a paycheck, booze, cell phone, pizza, cable and porn on demand.
I believe you are referring to Bread and Circuses Republicrats.
They are Republican/Democrat because:
their mommy or daddy was
their best or all of their friend(s) was
they dated this hunk or hot chick who was
they thought it would be cool
they got drunk at the county fair and signed up
they got promised free stuff
those other guys are rayciss
they are rayciss, but the party really isn't
they believe there ain't no free lunch
they want free lunch
they like donkeys, especially after
Shrekthey like elephants, especially after
Horton Hears a Whothey think (
fill in blank with name) is cool and they are a Republican/Democrat
You couldn't march in the protest if you were one
etc...
It is a brand, like Coke or Pepsi, meaningless in any sense to them except it is their brand, and they'll defend it with their sacred vote, right or wrong. Besides, they had to go to the principal's office once and that was enough principals for them.