Only the people doing it know the goal. I can speculate of course. It could just be standard 'fog of war' type stuff, or related to softening US public support for interventions against Russian actions in places like Ukraine. It could also have really specific goals you'd never guess without insider knowledge.
I completely agree about there being more than one actor here. I just suspect Russia has a non-trivial role in the phenomenon I mention in my OP. The bottom line is that today's Internet is loaded with bullshit and propaganda and as time goes on seems to become less and less trustworthy as a source of information. That's a big problem.
On the other hand, how much of the race baiting on the alt news sites is organic? How much of it would still be around if it wasn't the hot topic that everyone is being forced to pay attention to via the media?
Finally, what is the real long term strategic goal of these propaganda campaigns? It's hard to see foreign propaganda ever being successful enough to deliver a geopolitical victory.