Was there, though - or was that just what we all convinced ourselves?
To borrow your argument about one thing leading to another, this more obvious racism - the rise of Trumpism, the rise of the alt-right and the use of all that for political and self-enrichment ends - did come as a reaction to an event in recent US history; slightly more than one decade ago but not as long as a decade and a half. That event wasn't threatening, it wasn't illegal, there was no violence or political chicanery, it was a clear and obvious decision by the people (twice), it didn't lead to a socialist utopia being created from the powdered bones of patriot children and a grown up was put in power as a result.
These people have always been there, and they'll react to Biden (and doubly so for Harris) in the same way that they reacted then. They are the extremists, the actual nazis, the people who its probably futile to reason with.