It's not conceit that would make a person not want to identify with the war criminals/terrorists of the Democratic or Republican parties.
That's a perfect example of something that undermines independent political choice, i.e. the desire to avoid associating with 'deplorables' associated with a party, whether they are deplorable because of war-crimes, social-economic class status, or whatever they are deplored for.
In other words, what you could call 'dependent voting,' is when people vote for social reasons, such as virtue-signaling, appeasing workplace/family expectations, etc. Many people don't vote or even think about politics from an independent standpoint, but rather they do so from a socially-connected standpoint.
Registering as 'independent,' really is something different than actually voting/thinking from an independent standpoint. You could, for example, register with a party and still be independent enough to vote for a candidate of another party, or not vote at all. Independence just means free of bias and whatever else would prevent you from voting/thinking in ways that defy party/faction discipline.
You might even register with a certain party because you are independent enough to do so despite party/faction expectations about your beliefs. Let's say you are pro-life, or anti-taxes, but you still want to register/vote Democrat because you just see a carbon tax or transit subsidies as good for the environment and you think the Republican party is biased toward the oil industries and against public transportation. Likewise, let's say you are against taxes and welfare programs for the poor, but you are pro-choice and you're against the Republican party's moral agenda; then you might decide to register/vote Democrat despite actually being an independent that differs from both parties in various ways.