This is overly simplistic, but does fairly describe a certain part of the Democratic establishment. It's wrong on a few things, most notably the establishment's support for austerity. We've seen a huge shift away from austerity politics among establishment Dems since Obama's presidency. There's literally only a handful of elected Congressional Dems who might still buy in to the austerity shit, and that's because they're dumb enough to genuinely believe it's necessary, economically speaking.
The true part (and the part that's really at the heart of what's wrong with the party) is that it's a party of consultants and careerists (we could actually use more opportunists in the Democratic party). The consultants keep their status within the party by insisting on the importance of polls, focus groups, etc. to winning, and the careerists think the point of the party is a jobs program for good soldiers. Those who feel they've waited their turn react more negatively to someone they see as skipping the line than they do to anything Republicans do, because beating Republicans is secondary to maintaining their own place within the party.