As for me, it was fueled mostly by my belief that Americans (at least their decision-makers) are smart and rationally thinking people. They couldn't spend all those money (decreasing their own safety) in already lost conflict. I'm a rational man (or may be I just prefer to think so), and emotionally it's much more comfortable for me to thing, that behind actions of the leader of the second strongest country on the planet is a rational plan. May be criminal, but rational. I can imagine that American president wants to eliminate Russia by a out-of-blue nuclear strike and for that goal makes an outpost in Ukraine. I can easily imagine that the true goal of his investments was not "to defend Ukraine from Russia" (its simply impossible), but "to defend America from Trump".
But the idea, that all those actions were caused exclusively by stupidity and incompetence of decision-makers, sounds a bit terrifying for me. Thank you, it sounds pretty uncomfortable, but I can play with that idea.