> I remember a professor who blamed natural disasters on some states legalizing gay marriage as punishment from God/nature/etc

It's probably wrong to lump these religious/political views in with the nutjobs, but like you say, it isn't grounded in reality and that's a common thread. You can't reason with them either way, because reason had no part in their views to start with.

I don't think it's unreasonable to question the sanity of anyone who sacrifices the health of themselves or their children just to 'own the libs', but I suspect a lot of it is actually just blind trust in their party who stokes their deepest fears, repeats over and over that the other party is lying/dangerous, and tells them what they want to hear. I doubt very many are knowingly taking up opposing views out of pure spite for the other team, then coming up with excuses for it, but I guess that could be what's happening subconsciously.