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)

Same ... it's clear that attempting to convince my own family is just as effective as speaking to a charcuterie board. Want to breathe the smoke? Fine, go ham. I'm fresh out of pity for the science deniers.

I don't know why it's so hard to understand that breathing particulate matter into your lungs isn't a good thing... A child should be able to understand this. My 10 and 12 year old INSTINCTIVELY understood this... they pulled their shirts up over their nose on their own when we woke up and went outside on the first bad day.

"people died listening to Trump’s suggestion" is undoubtedly true, but are there any documented cases of someone actually injecting bleach, much less that leading to their death?