It's worse than that even. Having served as an election judge (and hence been obliged to assist those who needed it), many people needing help will ask "Which of these is the Republican option?" (where Republican = their party affiliation), even on issues that weren't particularly partisan, or national, or that even made sense.
The tact there being that party affiliation was more important than expressing their own choices, which isn't something that I understand in the slightest, especially as how centrist most candidates are.
It's pretty basic tribalism. "I am a Republican. Therefore, I will vote for the Republican option, unless I have an actual reason not to."
In front of that, there's probably, "My parents were Republican. My family is Republican. My friends are Republican." And so on.
%s/Republican/Democrat/g
This isn't actually wrong, per se. It's a basic affirmation of trust in one's close network. Some people go to church without bothering to believe in God; they go because they've always gone and their parents go and their friends are there and they discuss the football game or whatever. They're passionate about things because all of their friends are passionate about it.
The tact there being that party affiliation was more important than expressing their own choices, which isn't something that I understand in the slightest, especially as how centrist most candidates are.