The Democratic establishment is the biggest obstacle to progressive causes.
That much you knew. However, the DCCC is usually subtle about how they stifle progress. It's unusual for them to simply act like an extension of the RNC.

In a statement on the DCCC website, the organization stated its case against Moser thusly: “Democratic voters need to hear that Laura Moser is not going to change Washington. She is a Washington insider, who begrudgingly moved to Houston to run for Congress.” The crux of its criticism is that Moser recently relocated to the district from Washington, DC; that her husband is on the payroll of the fundraising firm she uses, Revolution Messaging; and that she once wrote something really mean about living in a rural Texas town.

It’s an unusual attack for a few reasons. Moser, who grew up in Houston before moving away, has caught fire in the race largely because of her pedigree as a first-time activist—after the 2016 elections, she launched an organizing tool, Daily Action, to make it easier for activists to bug their members of Congress. She was featured on the cover of Time. It’s a little strange to start off the year of the first-time woman candidate by stating that a leading Resistance activist is “not going to change Washington,” just as it’s unusual to see a freelance writer—Moser has written for Slate and penned a series of young adult novels—described unironically as a “Washington insider” by virtue of having once lived in the same city as the DCCC.

Even the Howard Dean-founded Democracy for America shot back and called the DCCC “Republican-lite cheerleaders”.
Moser's real crime is that she supports single-payer health care, paid parental leave and campaign finance reform.

So who does the DCCC want?

To that end, national Democrats have tended to favor Lizzie Fletcher, a corporate lawyer running a more moderate campaign. EMILY’s List, which recruits and backs pro-choice women candidates, endorsed Fletcher last winter. But Fletcher has her own challenges—she was the only Democratic House candidate in the state that the AFL-CIO instructed its members specifically not to vote for, on account of her law firm’s role in a union-busting case.

Every time I see the Democratic establishment sh*tting on a progressive, EMILY's List is always involved.
The Intercept headline puts it into context:
DCCC Goes Nuclear, Slams Democratic Candidate As Corrupt For Same Behavior It Engages In Regularly

The dropping of the opposition research on Moser came after The Intercept published an article Thursday morning highlighting a rift in the race, with the pro-choice women’s group EMILY’s List backing Lizzie Pannill Fletcher against Moser. The DCCC and EMILY’s List often work hand in glove. Meanwhile, candidate Alex Triantaphyllis, a former Goldman Sachs analyst, has told people on the campaign trail he was recruited by the DCCC, according to local Indivisible leader Daniel Cohen.
Fletcher, a corporate lawyer with ties to a mega-donor steel magnate, worked for a firm that routinely represents employers. The firm recently defeated local janitorial workers in a labor law case by studying social media feeds to ensure the jury had a healthy number of Trump supporters, a tactic it later boasted about publicly. Fletcher said she didn’t work directly on the case. But the local AFL-CIO made a rare non-endorsement in the race, urging residents to vote for any candidate other than Fletcher, and pledging to do what it can to defeat her.

This is just flat-out disgusting.
Based on fundraising, Moser is competitive.