Whatever it is that's driving people apart isn't exclusively an American problem.

This is the scary part. The entire world seems to be shifting right again. I think a lot of it how easy misinformation and disinformation is to spread with the ubiquitous social media now, but like you said, it's complex, and there likely isn't any single factor contributing to this.

Just to chime in on Covid - I think that was a symptom caused by a lot of underlying problems, and not a cause. Granted it had its effects, but under a rational leadership from the US I don't think we would have seen what we did ever get that far. The topic here (bird flu), measles, etc. are an example of how they are more of a fever indicator from a deep infection we've had for decades and just pretended things were fine. Hell, the failure of Reconstruction after the Civil War is the ultimate example of that bandage over a festering wound.

On the global stage, it's the explosion in communication tech with little to no oversight. It's not even the first time is happened in the last century. Radio, newspaper, television, whenever there's a new, faster way to disseminate information we collectively forget how important it is to regulate that shit before something bad happens. That, plus regulatory capture weakening the limits on already existing information platforms.

healthcare, and lack of job prospect in many stems field as a undergrad. almost no help in getting people into wet lab work outside of your degree, since it is the most important part of the degree