I think it is the "if you're not with us, you're against us" mentality driven ad absurdum.
Especially the US seems to strongly polarized that anything said by someone who could be considered left leaning, will mean that the entire topic is now a leftist topic and that you have to take the opposite stance to it, no matter how stupid it is. That's how topics like climate change ended up becoming so politicized (and not in the way it should have).

Not for the rich oil tycoons. But yeah, for the brain washed masses it must be exhausting. But I think that only furthers their rage and obstinence. They'ed rather that than admin they've been fooled or used.

It comes from the same place as the deeply held but mutually exclusive beliefs that the government is both totally stupid and incompetent but also so capable and efficient that they are somehow carrying out massive conspiracies on the entire citizenry.

They're not just doing it to do it

well that's part of it, but it's mainly "if we accept that climate change is real, then it's us who are at fault for it; as such we need to discredit and downplay it and anything resulting from it"

like they have a vested interest in saying that it's not a big deal, it's a conscious choice that they're making; they're not being stupid (or at least not in choosing to deny this)