This is not my concept, but I will try to put it in my words. The Democratic party has put together a large and diverse voter group; it was actually quite an achievement considering the diversity of views their group represents. But it also means it is inherently fragile. Given their own means, and time, such a coalition would naturally fragment. Already BLM has seen themselves being cut out of the Policy making process, and more is to come as Biden enacts policies, which harm one group or another. So how do they fix it? They create a boogeyman who is a composite of things, which each of the diverse groups can find something to hate.
That composite is the evil gun-toting white supremacist (and carrying a bible). Naturalist and environmentalist can only imagine the poor frightened woodland animal which is about to blasted into oblivion. Hard core liberals are also put off by his unbending attitudes, and adherence to traditional norms. Many groups are put off by their dogged support for the two parent nuclear home and faith. And they, of course, they imagine him toting a rebel flag while whistling Dixie, which allows minorities to dig deep into wounds from before their birth, where the evil supremacists did bad things. He is the perfect caricature of the monster which all these groups can despise. It gives them a point to be UNIFIED. Democratic leaders, aware of their fragile coalition is, realizes the need for just such a boogeyman. As long as ALL of their groups seem to hate the same thing, their hate will keep them unified. You will see a MUCH slower impeachment process in the Senate; the longer they drag it out, the longer the hatred can be focused, and perhaps even refined in some fashion. But even Senate hearings come to an end.
You see, without a common enemy, the coalition of the left is just too diverse to survive. With Trump leaving office, the primary glue which unified them, is fading away. And SOMETHING needs to replace it. We can all expect to be vilified for years to come.