He's implying we should retaliate against people because of their voting decisions, which is a hugely shitty thing to do. There is no black-and-white in politics, and someone who supports Trump doesn't mean they support literally everything Trump has ever said. But thanks to the divisive bullshit of this campaign, everyone hates each other.
Not simply a voting decision. As DHH explained, "this is a man who's a Trump delegate! Keynote endorser at his convention! Political action and operative."
I think most people who vote for Trump would be happy to be nominated as his delegate. All things aside, it is seen as a social honor to be a delegate.
By invoking the Resistance, pg compared Trump to Hitler. DHH was merely probing where the line falls between Hitler and the other Nazis in that metaphor. DHH didn't bring up black and white, pg did.