The problem with your explanation is it assumes white men are more resistant to manipulation than women, black people and Hispanics. I think you should reconsider saying that.
Oh, and about that huge group, of "millions of voters"? No evidence of that in the election polls. Why is that?
Out of 235 Democrats that won seats in the house, you name 3 so-called Progressives. In the past, I counted 6. That's 6 out of 235. That's not "good". That's barely hanging on. The evidence of a nascent Progressive movement is in your head and not in Congress.
The Democratic Party already supports the policies your so-called Progressive movement professes to be "revolutionary". If you want campaign finance reform, elimination of gerrymandering, a more responsive government, strengthening of social safety nets, are you going to look to Republicans to provide them? The last I saw, Republicans came within a few votes of privatizing Medicare and social security as well as repealing the ACA without anything to replace it. So, good luck with that.
As far as blacklisting of consultants who work for candidates that are primarying an incumbent Democrat? The DCCC has every legal right to do that and it's in their charter to expand Democratically held seats in congress. Its not a conspiracy if its a stated policy out there for everybody to see. When you run as an outsider, don't expect help from the insiders. Yet your kind cry bloody murder when you find out that the DCCC is about supporting the strongest candidates, not the ones you want. That entitled attitude runs deep in the so-called Progressive camp.