> Can somebody explain the psychology behind these beliefs? I'm pretty sure they know how coal is mined. They must surely have heard about the black lung disease and COPD.

Of course they have? I'm sure you've seen pictures of miners back in the 19th century covered in soot? Why would the wealthy and powerful care about people who aren't them? You can't assume that everyone everywhere thinks "powerless people suffering and dying is wrong", that's quite demonstrably false. It might even be a plurality of people on earth who could not care less about the suffering of those outside of their immediate family and friends.

> I'm looking for an answer that doesn't assume that they're stupid or insane.

they just dont care! Why assume that people who ran for political office actually care about the welfare of others?

if the question is "why do this coal stuff when it's also unnecessary", well that gets into another MAGA value which is "dominance". That is, making people suffer and accept things that are horrible is also a big power play. Just watch any Game of Thrones episode for examples.