> we were pretty f*in' divided during the Bush years, and the GOP stopped at nothing to go after Clinton.
Its quite weird, because the exact same narrative of unprecedented polarization has been used under Clinton (during the bipartisan neoliberal policy consensus), Bush, Obama, and Trump (with Biden, its at least usually acknowledged as a continuation of that under Trump, not new), with most major voices just seemingly forgetting the unbroken succession of preceding instances of the same narrative, pretending whatever is currently happening came recently, out of the blue without warning.
I think you can justify the claim that there was a real increase in political tribalism resulting from the resolution of the long post-WWII set of political realignments that was particularly evident from about the 1994 midterms and the Contract With America through today. (With some signs as far back as the 1980s as the lines of the new alignment started to become clear and the parties really accelerated movement toward their new polarity, where previously major ideological divides weren't aligned with the major partisan divide, so that ideological factions, to succeed, had to work across party lines.) But that's not as sexy a narrative as “suddenly we woke up in this election cycle with divisiveness that just came out of nowhere”.