I don’t think your definition of a NeverTrumper is accurate. I was NeverTrump in the primaries, but even I concede that Trump is/was preferable to Hillary Clinton. So maybe this definition of yours paints with too broad a brush?
There is a world of difference between the primaries and the general—and even that is an understatement. The primaries are when the party’s candidates duke it out for the nomination. It’s one-hundred percent legitimate for conservatives to select and campaign for their favorite candidates—and that includes at the expense of those candidates they believe would be a mistake.
The general is almost always a binary choice. We have a two party system, so the choice is Democrat or GOP. When you campaign hard against the GOP candidate, that is the exact equivalent of campaigning FOR the Democrat. Some of the more honest Never-Trumpers admitted as much. They came right out and said they preferred Hillary.