I certainly found plenty of folks who were not only okay with the DNC's position but who were actively happy with Harris as the nominee.
Black people are, however, not a monolith. I'm quite aware of the differences between the many different sets of ideas (everything from hoteps to DNC-paid shills to people who genuinely liked the Harris platform to black anarchists/commiunists/ ex-panthers/ etc) and it's highly reductive to try to make the claims you're making here about "what black folks have learned".
As a person who genuinely believes actual leftist (communist and anarchist) politics are legitimate I found plenty of folks who abstained or tried to hold the DNS to change their policy.
But regardless of the "harm reduction strategies" or how legitimate you think having any semblance of political representation, the fact remains:
the democrats lost.
Unless you want to concede that "the party can only be failed, it cannot fail the people", the reality is that the party could have changed its policies and accommodated groups that abstained and perhaps won.
You can claim that the voters are just fools, but at the end of the day very few of us have any power at all over the DNC platform so it's simply bizarre to blame us for their horrible, provable failed choices.
What you’re arguing for is only single-round optimal, but multi-round suboptimal — much like defection in the Prisoners Dilemma is defeated by trust strategies the Iterated Prisoners Dilemma.
Until you show how it’s multi-round optimal, you haven’t addressed their critique.
Right now it looks like you drained the baby with the bathwater.
My bigger question: Why would you make the foreign issues dominate your national issues?
But to answer the first, I’ve heard directly from party strategists that they look for people who vote, but not in a particular race. They can’t identify them directly, but a higher ballot submitted count than (eg) presidential vote count is a signal that they can gain voters in that area — which they follow up by surveying independents, etc to see what policy issues they’re concerned with.
The argument is that by not voting some rounds, you influence their platform in subsequent rounds. If you vote for them regardless, there’s no incentive to optimize their platform to address your concerns.
What you're advocating benefits the greater evil ten times as much over a 20-year timespan. They're absolutely loving you. The more Bidens, the more Harrises, the more Clintons, the better for them.
You know why China is doing so well? Because they still remember how to think in the long term.