Harris has campaigned appallingly, even at this late stage she is often doing one event a day. She is a poor campaigner in general - look at the 2020 Dem. presidential primary.
There was no primary for the Democratic leadership.
The number of Americans who ‘think the country is going in the wrong direction’ is at an all time high.
She fails to articulate policy and has no ready answer for what separates her from the current administration of which she is Vice President.
She is a far, far left candidate - look at her voting record. You may like that but it’s foolish to think others won’t object. It’s foolish to think interviews with her saying she would fund genital surgery for illegal immigrants in prison won’t have an impact, that supporting legislation that ties federal funding to letting boys and men play in women’s sport and be given access to women’s bathrooms doesn’t turn people away.
You can call people names for not voting for her or you can look at why - and who - the people are who aren’t supporting her. The cost of living is up, life expectancy is down, the knowledge their children’s lives won’t reach the same standard as their own. The Democrats move away from being a party for workers to being a party of the technocratic elites. (See fundraising).
The Harris campaign has fundraised 10s of millions more than Trump’s. They have an incredibly effective on the ground team, mainstream media is on her side, she benefits from running against a polarising opposition figure - and yet still she fails to appeal to people. Maybe instead of blaming people for not voting for her and calling them names, look at why.