I think this is a huge part of it but there is certainly a lot of nuance here. We have a phenomenally funded, equipped, and trained military, but in the last 20 years it’s been shown to be only moderately effective at addressing the threats in the world that have a small fraction of the resources our military does with few exceptions (naval might is probably the largest of those exceptions). So even problems we think we should be able to solve we barely can.

There is also large and growing wealth disparity which drives the tribalism deeper and makes many folks dig their heels in to positions that just aren’t based in reality (see anti-vaccine and lockdown sentiment around COVID as but one example). Couple this with the majority of Americans being truly terminally online and being stuck in echo chambers that just further ingrain the basis they hold and it causes a lot of vocal Americans online to lash out irrationally.

I would like to offer OP a view that we aren’t all like this though. For many of us our incoming government, the corrupt people they are tagging to lead our various institutions, the incomprehensibly rich heads of various companies, and the brainwashed cults that worship them all are sources of deep shame. I can only speak for myself, but my friends, close coworkers, and even a few of my family all feel this way. Please don’t write off all Americans because of the loud, obnoxious jerks you have to see in many places, some of us are pretty decent people that really want to make the world a better place and help everyone we can.