The degree to which Russia is tangible relative to the DNC is entirely based on who you see as a reliable reporter; the DNCs “meddling” is no more tangible or open than Russia’s in any real sense, it’s all just twitter reports, MSM articles and “he said she said” anyways. Contrary to popular internet opinion, most people see the MSM as reliable to some extent. Think: people who watch the nightly news or have NYT/WaPo/CNN apps as their primary news apps. Additionally, in the event Russia’s interference isn’t on the minds of working class people the DNC’s alleged interference almost certainly isn’t either, outside of working class people already supporting Sanders (and not even all Sanders supporters agree with your DNC is worse than Russia stance).
You mentioned “Washington bubbles” but really the internet progressives tend to be in bubbles just as much if not more. If you’re only talking to College age liberals and internet progressives, you’re not getting a picture of working class Americans any more than the “Washington elite” are. The Democratic base is maybe 65% moderate and 35% progressive. The majority of the Democratic base sees people like Joe Biden, Hillary Clinton, Nancy Pelosi and the rest of the establishment as generally competent. Note that is not the same as voting in primaries for Clinton or Biden, but just seeing them as decent, viable politicians. It’s a hard sell to most of them that the DNC is this giant manipulative entity, and that Russia is not a malicious player. Like, the Muller Report was a huge story and most Democrats I think agree with the conclusion and evidence that turned up in it.
I say this as a likely Sanders voter (if Warren and Steyer are unviable or out). The biggest problem with Sanders has nothing to do with Sanders, it’s that his base and volunteers have deluded themselves into thinking their echo chamber opinions on the internet somehow vibe with the majority of the entire democratic base. I think that’s not really the case in a lot of ways, as we saw from the Yang campaign a lot of social media hype is in no way an indicator of how voters will vote in the primaries or how much their ideas resonate.
I think you bring up some decent points when talking about democrats, but there's a few things I think you might have misunderstood-
You're talking about democrats, I'm talking about Americans as a whole specifically the working class and also a lot of whom are independents/nonvoters who feel disenfranchised and have no faith in the political processes of this country.
Also, I'm not basing my opinions off of internet progressives and college age liberals. I am not in college and outside of this one thread and one channel on a discord server, I don't really talk much politics online tbh. I myself am part of the working class and have lived in various areas where I've had contact with many other working class people (Miami, Homestead, Tucson, Orlando) in various areas. Of course, that is just my personal life but I also keep up with polls the best I can especially during this election cycle- polls from all over that interview many different people.
So again, you say the democractic base see people like Pelosi as competent but I'm talking about working class Americans as a whole.
Also, I take a bit of issue even within the democratic base on the percentage of moderates vs progressives when the exit polls out of Iowa and New Hampshire primaries recently both showed that 70% of voters supported Medicare for All, which is to me at least one of the "litmus tests" on whether you're a progressive in the democratic party or not. Of course, I don't think the base is as progressive as we would like it to be but I think the narrative that the base is mostly moderate is misguided as well.
I think that most people in the democratic party, at this point, still see a moderate as electable for taking down Trump (although that's fading as Bernie's momentum grows). However, I don't see these people as all staunchly ideologically moderate. For example, if you look into the cross-tabs of Biden voters many of them have Bernie as a second choice and vice-versa. Voters are not always ideological in their approach, especially when the MSM has been hammering into their head that Bernie is not electable and that [insert centrist here] is the best chance at taking down Trump instead. Precisely because more people see these media outlets as viable than progressives think (like you mentioned earlier), they might support moderates when they themselves aren't necessarily moderate, because their main goal is defeating Trump.
The points you make I think are very clear with (mostly) white, affluent/affluent-ish, educated liberals. They are the audience of MSM reporting in places like WaPo and NYT and CNN and tend to be pretty in tune to this stuff (also seem to be the most in tune with Russia stuff). This seems to translate as well in their shifty support of the candidates. Their vote has been moving the most between Pete, Amy, and Klob. I think your points also ring true somewhat for older working/middle class people as well, who seem to have been shifting between Biden and Bloomberg largely on electability issues. This is all based on trends in polling crosstabs in the recent months for this primary election cycle.