On the one hand, yeah. Worrying about stuff that you have barely any control over won’t get you far. But on the other hand, that guy’s vote counts as much as yours. And if he already believes such silly conspiracy theories as the flat earth theory, he will be easily swayed by whoever is the loudest contrarian.
Yah, it’s not so much what he believes, but that he displays a lack of critical thinking skills or even common sense. That’s just how it came to the surface.
Right and that should be the target of our efforts. Not fighting over scientific research they’ve already decided to reject. Encourage them to think more critically. You can only encourage someone when you have their ear. You only have someone’s ear when they’re comfortable around you. Demeaning someone’s intelligence and telling them their world view is a toxic lie, is a quick way to convince them they’ll only ever be at odds with you.