I'm still baffled the democrats wouldn't have put someone else up, they had the chance to throw anyone in against Trump, and even at the last minute, and they picked Kamala, with a clear attachment and track record with Biden. Similarly, I really wish the Republicans wouldn't have put up Trump again. With the right campaign, they could have picked many different people and had a pretty good shot to win without driving more division.
Your confusion with Kamala is due to a misunderstanding of the nature of the party. The whole "danger to democracy" schtick talking point they espouse tells you exactly what's going on. Trump won the nomination because that's what people wanted. The Democrat party had already picked a different candidate, in case you don't remember. You weren't allowed him. This has been a theme.