Maybe the best way to look at this is to recognize that people have concepts of how the world should look like, naturally that usually includes pleasantries for them. And when the world does not match their predictions, they want to correct for this error. Of course depending on cognitive patterns (which depend on exposure to others' cognition, eg. upbringing, peers, and all their previous experiences factor in to path dependence) one might try to look into themselves, look for their faulty base assumptions, look for causes external to their own sphere, and so on.
Normally, people who are not familiar with the problems of borders, the arbitrariness of them, who grew up in a culture that never experienced a downsizing country, a war in their country, stories about how political persecution and/or absolutely bleak prospects drove hundreds of thousands (or millions) of their fellow countrymen away are not going to be very understanding of these problems. On the other hand they will understand that their life is not going as well as they would like it. And they are caught by the meme net cast by whatever lucky political group. (And "blaming the victim" fused with "the outside enemy" is a pretty proven strategy for populists.)
And populists always advocate for more power to themselves to fix things. (Obviously, politics is about power, and populism is pretty much the shit tier direct marketing of politics.)
Hence the thinking of "america first", "make america great first", before we deal with whatever is outside our borders. This also implies that listen to "americans first", and then listen to any external criticism. (This is again always a pretty great strategy to consolidate power - a form of divide and conquer.) And naturally, this has the effect of basically diverting the attention away from global issues.
And since we're living in a global world for quite some time, without at least partially understanding global issues making sense of the local ones is a fool's errand. Because a thinking that tries to somehow understand everything locally inevitably runs into "outside powers caused this to us", and this feeds powerlessness. (It doesn't matter that the USA has and had a very significant factor in shaping that "outside world".)