Matt Taibbi has carved out a position as a provocative and honest progressive journalist, as well as a vivid and entertaining writer.  Writing at Rolling Stone, he enhances that reputation by being bluntly honest (from his perspective) about why the Democratic Party has fallen to its weakest electoral standing since 1929.  He disdains both President Trump and the Republicans, so his mission is to understand how it is possible to lose to such reprobates.  He writes:

The unspoken subtext of a lot of the Democrats' excuse-making is their growing belief that the situation is hopeless – and not just because of fixable institutional factors like gerrymandering, but because we simply have a bad/irredeemable electorate that can never be reached.

This is why the "basket of deplorables" comment last summer was so devastating. That the line would become a sarcastic rallying cry for Trumpites was inevitable. (Of course it birthed a political merchandising supernova.) To many Democrats, the reaction proved the truth of Clinton's statement. As in: we're not going to get the overwhelming majority of these yeehaw-ing "deplorable" votes anyway, so why not call them by their names?

But the "deplorables" comment didn't just further alienate already lost Republican votes. It spoke to an internal sickness within the Democratic Party, which had surrendered to a negativistic vision of a hopelessly divided country.

Things are so polarized now that, as Georgia State professor Jennifer McCoy put it on NPR this spring, each side views the other not as fellow citizens with whom they happen to disagree, but as a "threatening enemy to be vanquished."

The "deplorables" comment formalized this idea that Democrats had given up on a huge chunk of the population, and now sought only to defeat and subdue their enemies.

This is undeniably true and has been obvious to most of us on the right.  But our views cannot penetrate the blue bubble precisely because we are deplorables.  Taibbi, on the other hand, is calling out his comrades and enjoys a lot of credibility among them.

But he sees only part of the problem:

You can't just dismiss people as lost, even bad or misguided people. Unless every great thinker from Christ to Tolstoy to Gandhi to Dr. King is wrong, it's especially those people you have to keep believing in, and trying to reach.

The Democrats have forgotten this. ...

They don't seem to have anything to say to voters in flyover country, except to point out that they're (at best) dupes for falling for Republican rhetoric.

But "Republicans are bad" isn't a message or a plan, which is why the Democrats have managed the near impossible: losing ground overall during the singular catastrophe of the Trump presidency.

This is sound strategic advice.  But the Democrats cannot act on it for a reason that Taibbi does not mention.  The kind of Democrats who disdain Trump voters, and indeed much of middle America, have an enormous psychological investment in being better than these people.  Their egos need constant reinforcement that their personal investment in education and careerism has paid off, that they have achieved a higher moral and intellectual ground than the hoi polloi.  

Their own sense of self-worth becomes in part dependent on the other (that bugaboo of the progressive mind) being bad.  Normally, when leftist intellectuals blather on about "the other," they have in mind the oppressed, who can be pretty much anyone but heterosexual Caucasian males and the women who cleave to them.  It is this remnant that still constitutes a solid majority of the voting public, which is available for potential demonization in the leftist mind, since it is not a "protected class" (why isn't this status called being an "unprotected class"?).  So this group, that heavily voted for Trump, is the enemy that many progressives need if they are to validate their inflated notions of their own importance, erudition, and all-around worthiness.  

It's hard to see the left acting on Taibbi's observations and reaching out to those whom they scorn.  It comes at too high a cost to their egos.