That's part of it, but the other part is so much worse. The DNC and the Clinton campaign strategy was to elevate "unelectable" far-right nutjobs like Trump so that the Democratic party could intentionally pivot to the Right and still look like real opposition by contrast. They saw the writing on the wall ever since Sanders (and left-leaning policies in general) started gaining mainstream popularity in the late 2000s. The Dems are beholden to the same corporate billionaires as the Republicans, and the mere whiff of Leftism-lite made them all terrified that they might become slightly less wealthy under a SocDem government, and that "we the people" might become slightly more influential in said government.