Don’t they understand what’s happening?

No. Overwhelmingly, no, they don’t. The MAGA crowd is stuck to their pants with glee, the liberal crowd is going “oh well, we’ll get em in the midterms,” and about another third of the country is just brain-dead clueless about all of it. Maybe a few thousand people in the US actually understand just how close we are to cascading systemic collapse.

That’s a strange conclusion you got to. 96% of all mammal life on Earth is either humans or animals specifically bred to be our food. One species; 96% market share. Over 5000 other species combined only are 4%. Because we killed them all via predation or taking their habitat.