American elected Obama twice so I don’t think that Harris being black had anything to do with her not being elected. Maybe Americans aren’t ready for a woman, I don’t think that is true but who knows. Just because she didn’t win doesn’t mean the voters were racist or hate woman. Other candidates may have been more appealing for valid reasons.
My issue with her was she acted too much like a politician. She seemed sometimes to own up to her tough on crime stance and then would pivot to try to downplay that history. I hate the “anything to get elected” stance that politicians take.
One of the reasons I loved Bernie is he just took a stance and kept that stance even when he got pushback. You might not like his positions but you have to admire his integrity.