The point of guaranteeing your vote in the general election is to make yourself and your interest group an invaluable base of support anyone in the party will need to succeed in a general election. Once the party has been made dependent on your group, you can pressure them via primaries, running and voting for your own candidates, making yourself and your interest group an invaluable base of support to win in a primary election.

We've actually seen this happen in real-time with MAGA, which has virtually taken over the GOP. They vote red in every general election, participate in every primary, and as a result are vastly overrepresented in the GOP. The difference of course, is they're reactionary authoritarian nationalist, and we're not.

This isn't specific to MAGA, they're only special because we've been able to watch their take over of the party, and now slowly burn it down with incompetence and unpopular policy. These changes have happened to both parties in the past, many times, and in parties all over the world.

Then it's a problem comparison issue. Ethically, you go with the least problematic candidate.