Biden telling everyone repeatedly that his first two criteria were "woman" and "person of color" guaranteed that this was going to happen, so I'm not sure why you're surprised.
Biden chose the most conservative possible candidate he could, a law-and-order prosecutor, in exactly the same way that Hillary picked Tim Kaine. (Yes, Harris is definitely better than Kaine.)
If you're an actual leftist in America, this is part of the eternal drumbeat from the DNC - "Your commie ideas are worthless. You will never get anything from us. We hate you."
So this puts me in a nasty position.
I believe that if the US more or less gets over COVID by November 4, and Trump doesn't meltdown completely (always a possibility with mentally ill people), Trump is near certain to win - because Americans are stupid and have a short memory, and because Americans are racist and sexist and probably 150 million of them would never allow a Black woman anywhere near the Presidency.
So rationally, for me to root for Trump losing, I have to root for the virus winning. Great choice!
Better solution for me is to stop caring about what your dysfunctional and collapsing country does.
Sorry - you're a fine writer and your politics are generally good. I'm not attacking you personally - I'm completely and thoroughly sick of America, the country.
I spent far more money than I've ever spent on any other thing to leave America, it devastated my career, and yet I can't bring myself to regret doing it.
Still, the best of luck to you in the election. Trump must be defeated.
It's a shame the rest of the world have to rely on the feckless and spineless Democrats to save us from the rapacious, psychopathic and delusional Republicans, which given their 40-year record of abject failure in pretty well everything, is like hoping Elmer Fudd would save us from the Nazis.