We've always been tribal. We fought a civil war over our tribalism, and we never really got over it. We tell ourselves that we're a "big, bold, beautiful" tribe precisely because we're not, and we're hoping to talk ourselves out of that.
Tech is certainly exacerbating that. We techies like to tell ourselves that we're purely meritocratic, but that's mostly because we've always come from a fairly narrow slice of tribe. As more excluded people try to get in, the underlying distrust of others comes to the fore.
I think one of America's key virtues is our ability to ignore each other. We expanded into "empty" space during the 19th century. (It wasn't empty, but hush.) In our cities, we developed the virtue of politely pretending each other didn't exist. The online domain removes the necessity of that virtue, and our underlying dislike expresses itself.
All of which would be OK, if it weren't for democracy. Democracy is a tool by which we get to force our opinions on each other. If it were just limited to sniping at each other on Facebook, we'd be fine. Even "canceling" each other is OK: it's a big empty space, and you can find some other place to be.
But now, people's opinions intrude on the real world. It's one thing to say you don't like a group; it's another to have them physically removed. When you "raise tough questions", you might be helping protect people, or threatening their life, liberty, and property.
Rather than being a "big tribe", I'd say that our key virtue is being live-and-let-live. But that conflicts with America's other key virtue: our love of getting ahead, and fear of being unjustly held back. The latter encourages is to innovate and become wealthy, but it also indulges our underlying dislike of each other.