You can systematically murder more groups than just 1.

If you support one genocide for your own personally benefit what's to stop you from supporting another? You're morally bankrupt and completely irredeemable at that point.

If it was that easy, we wouldn’t be having this conversation.

It is that easy! You just don't want to admit. You're operating on an absurd moral plane where you think one set of genocide supporters is more redeemable than another. At that point you've already accepted the inevitability of fascism and you're just trying to make a bargain with it. I'm here to tell you fascism doesn't work that way. If you give it an inch it will take a mile.

you’re arguing that doing nothing is the morally superior response.

You can actually do things that don't require you to carry water for genocide supports. Go to a protest and connect with likeminded people. Organize your workplace or community. Engage in civil disobedience against unjust state violence. Instead of pretending that the only choice that matters is the one where you spend five seconds filling in one of two boxes every four years, do something that actually makes a difference.