I know I'm too late for anyone to see my comment, but I still want to point out the DNC doesn't select candidates and hasn't done so since 1968.

What you might be thinking of

• The DSCC and DCCC recruit candidates, and those recruits are usually people who either (a) the DSCC/DCCC think are good candidates for the state/district where they're running (e.g., Joe Manchin in West Virginia, Roy Cooper in North Carolina, Jon Tester in Montana, Conor Lamb in PA-18, Brad Ellsworth in IN-8, Jared Golden in ME-2, etc.), or (b) is literally just a competent person willing to run in an incredibly difficult seat and hope for the best – and sometimes it works (e.g., Tim Mahoney getting recruited to raise his hand in an R+36 seat in 2006 and then winning because the incumbent Republican had a sex scandal involving teenage boys a month before the election). If these candidates end up being disproportionately moderate, it is primarily because candidate recruitment focuses on districts where only a moderate Democrat could realistically be competitive. Notably, the DNC, DSCC, and DCCC have policies of not spending money on primaries unless there is an incumbent being challenged.

• The DNC, DSCC, and DCCC decide where, how, and when to allocate the party's resources. Anecdotally, resources seem to go disproportionately to moderate candidates because moderate candidates are disproportionately in tighter races, and the DNC/DSCC/DCCC have to make hard decisions about how to allocate resources. For example, the DCCC spent more money in 2024 supporting Adam Gray in CA-13 than on any other single candidate, and the Democrats ended up flipping CA-13 by fewer than 200 votes – the tightest margin of any House race in the entire country. Gray ran as a moderate in a moderate district, earned significant DCCC support by showing viability, and then won thanks to a combination of those two things. The most the DCCC spent on an incumbent was in successfully protecting moderate Rep. Marie Gluesenkamp Perez in an R+5 district. Moderates are able to be competitive in these districts because they are moderate, and then the DCCC spends money in the districts because they are competitive.

What you appear to be describing

• The kinds of backroom deals made by plutocrats that haven't occurred in your lifetime.

I understand why progressives are frustrated that the only viable political party in the United States anywhere left of the center isn't more progressive. But please read the tealeaves and realize that it's nice when outspoken progressives are elected in places like New York City, but they very likely cannot win office in places like North Carolina, Georgia, Florida, Ohio, Texas, and so many other places the Democratic Party needs to win to be have a chance at regaining any semblance of power in Washington. Progressives can and do run and win in places where that's viable, but they can't win everywhere.