I wonder if a lot of upper middle class white college donors (includes many Jewish ones) have soured on Dems in recent months and the new flare up of protests reflects decreasing interest in the party.
I suspect it both, a combination of what you said and also progressive donors souring on biden due to his support for israel.
Leftists still think every Trump voter is a white nationalist. Every Biden 20-Trump 24 voter I know is pro-choice and just isn’t interested in seeing a reprise of the old Russian empire pogroms with the implicit approval of the Democratic Party through the academic left.