Are you listening to yourself? Trump is crazy/senile. Many of the people that support him know this, but will continue to support him because he appoints the (R) judges they want. He could be the craziest person on the planet, but his supporters just won't care as long he can be relied upon to deliver the courts.
A month ago, I though Harris had a good chance at winning. But as we got closer to election day, ads, headlines, and commentators focused more and more on how bad Trump is, rather than what she stands for or promises. That's why she lost. No one was going to change the minds of any Trump voters. She needed to get undecided/swing/unmotivated voters to vote FOR her, rather than vote against Trump. "We're not going back"? Fine, I don't want that either, but instead of repeating that over and over, how about you remind people what it means for a Harris administration to move us forward? You can't do that because you're keeping us in bed with Israel and people are concerned about the implications from that? Yeah, she was going to lose to the "pet-eating" douche.
Say whatever you want about Trump and his supporters, and sure, there's plenty to disagree with. But, they had someone they were voting FOR, and that means more than being scared of the alternative.
Harris, Biden, and Clinton are not progressives. The DNC shut out a popular progressive in 2016 and learned nothing then. D voters as a whole are too quick to dismiss anyone that might be a threat to their main candidate. Of course, Sanders running independent in 2016 would've secured an even more humiliating loss for Clinton. But it would've steered us toward a more productive conversation by now, and Trump likely wouldn't have won a second term, or probably even another nomination. Instead, let's move to the right and try to appeal to those "moderate"/"swing" voters.
I don't think Biden would've won without Trump's (mis)handling of the pandemic. There's certainly misogynists out there that would never vote for a woman, but the pandemic was the other major differentiator. The DNC is fine with serving their donors with the most appealing not-Trump puppet, rather than getting a candidate that the citizens genuinely want to vote for.