Because it’s part of an entire worldview, an entrenched information system (I.e. framework for narrative, how the story is being told), with fully intertwined rationale and philosophies of justification. In there are woven many positive emotions as well, and rhetorics hitting the right emotionally resonating notes—patriotism, belief that the west is the light in the darkness, that you’re the good guys, doing the right things, etc. Behind it is also a foundational belief that US is powerful enough to crush anything it doesn’t like, so who really cares about nuance—sometimes, not even conscious.

To give up this worldview, one has to give up a lot of deeply held assumptions about one’s life, one’s self identification, one’s “tribe”, etc. It’s unlikely to happen just with some debate here or there, or reading some news stories from far away.