Wrong Framing. Institutions Created this Beast.
When you say, “tribalism that we have been creating offline for decades is being imitated and accelerated online,” you’re effectively making an absurd claim. Tribalism predates civilization. Civilization then institutionalized tribalism. The reason tribalism is so virulent and visible online is because the political systems we created perpetuated it.
First we shape our tools, and thereafter our tools shape us
Suggestion that there are “only two plausible outcomes,” is in error. (see my articles, Only 6 Possible Outcomes in Next 20 Years [ — 4 are Bad — ] and longish, but detailed exposition, Macroscopic Evolutionary Paradigm)
Having spent a lifetime looking at this very problem complex, absent an nested evolving systems frame everything becomes relativistic game of he said, she said. That, in turn, exacerbates the problem complex. (see my article, A Message From the Bow of Civilization)
On my Medium publication, A Passion to Evolve, there are numerous articles addressing both the problem and potential solutions if interested.