See the part about the Democratic Party actively working against progressives, to the point of funding propaganda against them. The Dems saw the Tea Party and care more about avoiding that with progressives than they do about running candidates that can either beat the Republicans or serve the people.
And from what you just said: you'd better have never once blamed progressives for losing the Democrats an election if you're taking the "progressives are too weak" position.
Gonna continue to call bullshit here. The grassroots movement failing to gather momentum in the face of propaganda at the cost of the nation's future is not the same as the Democrats blaming a minority for their own failures. Not even a little bit, can you please reflect a little on how absurd that claim is?
You're also not comparing apples to apples here. First: the Tea Party was an unknown element, there hadn't been a growing fringe movement like that within a major party for a century. The Democrats had the benefit of seeing that happen on the right. Second, the Republicans were willing to embrace the crazy of the Tea Party for the sake of their continuing victory. Very much in contrast, the Democrats are very clearly willing to sacrifice national victory in order to keep progressives down. Three elections in a row they've insisted on running the most centrist candidate possible, resulting two very predictable losses and one surprising victory.
Democrats insist on siding with money and corporations every time, their failures are their own fault, and very much also the fault of their supporters.