Most people's grievances right now are the economy and inflation. And they want change. They want the elites to have less control over their lives.
Sure, the right has some crazy ideas. So does the left. But the middle decides elections because they are the swing voters, and the middle's main grievances are the economy and that they feel helpless in a world where the wealthy control everything.
Even if their thinking is based on false premises, as you claim, they have legitimate grievances. The Democrats will never get their votes if they don't address the grievances with a realistic alternative plan.
I think I know who you are talking about. The loud and proud ones. But what the loudest people are saying is no necessarily what most people are thinking. So you can't assume everyone thinks like them.
I think the problem is that many Democrats are stuck in an information bubble, and instead of listening to the other side, they demonize them and cancel them. It is hard to figure out what the other side is thinking if you don't actually listen to what they are thinking.
I think that America rejected leftism, not liberalism.