I was on the train re-reading the article and felt compelled to really write down my thoughts. Apologies for the wall of text, but I think you are being incredibly generous in your analysis. Look back at the structure of the column and the flow of the analysis.
The first thing to do is look at the lede. This is the idea/argument/analysis that the writer wants to leave you with. Newspapers/columnists know that many readers may not finish the entire piece - this is the message they feel is most important. In this case it very squarely states Clinton was
"damaged by a significant decline in turnout among black voters, especially in a few high stakes states", followed by the money quote from the Washington Post.
It then summarizes percentage of black voter declines, highlighting critical swing states while pointing out states where white turnout increased. It then transitions to numbers that suggest other traditionally Dem voters (Hispanic/Asians) increased turnout, but that "neither boost was enough to save Clinton." (My analysis - The other minorities did their part and then some, but it wasn't enough to counter black people staying home)
I find it interesting that a 3.8% increase by Hispanics is described as "significant" but a 3.5 and 5.2% increase in white turnout in Florida/Pennsylvania (which obviously directly aided Trump) doesn't deserve a similar adjective. This subtly pushes a narrative that Hispanics did their duty by "significantly" increasing turnout - but that this increase couldn't negate lower black turnout.
Next paragraph squarely states that had turnout remained at 2012 levels Clinton would've probably won the election. Think about the underlying message. The only deviations in turnout that would have changed the result, if you follow the logic of this piece, is the lower black turnout. Remember that the piece very clearly stated that WHITE turnout modestly declined (which would presumably have HELPED Clinton) in the 3 states that decided the election (MI, WI, PA) and Hispanic/Asian turnout was lower in 2012.
NOW, neither Slate, nor the writer or the Dem establishment want to appear to blaming ONLY black voters, so they have to throw in mitigating factors (at the end of course - there is no caveat to the pronouncement in the lede). One of the most profound statements of fact - "It is clear that Trump managed to convert a significant number of Obama voters, especially among the white working class in the aforementioned swing states" - is IMMEDIATELY followed by the notion that only if black people would have turned out in greater numbers that they could have "blunted the impact of those [white] losses and might have even put Clinton over the top. As anyone who watched election returns will tell you, Clinton's inability to hold white Obama voters was crucial in her loss in places like PA. But look at the writer's analysis.
"IT IS CLEAR" that Hillary's inability to hold those voters aided Trump. This is an undeniable fact. There were no external (voter suppression for instance) factors that could account for why these voters abandoned Hillary. They simply didn't like her or her policies. And there is no analysis as to why this is the case, they are given the benefit of having a choice of who to support.
"BUT IT SEEMS" (i.e. I have no actual proof) that higher black turnout COULD HAVE put Clinton over the top. (In other words, having to choose between the objective fact (Clinton lost Obama voters) and a
belief that can't actually be proven - the writerpresent the unproven hypothesis as the primary factor).
And even worse is the way that they casually dismiss the effect of voter suppression, contrary to reams of evidence that these efforts are ONGOING.
https://thinkprogress.org/2016-a-case-study-in-voter-suppression-258b5f90ddcd
The message I get is essentially that voter suppression is no excuse since we've known for 4 years that the Republicans are going to try to depress turnout.
Finally, anytime a reporter wants to talk to "real life black people" they make their way to the nearest barber shop! I mean why go out of your office and talk to your black colleague when you can demonstrate your authenticity by proving you're not afraid to be the only white woman in a black barbershop.
Words have meaning, especially to a person who makes their living with their writing. Think about the following passage:
"Only two could
muster the enthusiasm", and even worse, one of those two "wrote in himself."
I guarantee you that a SIGNIFICANT percentage of white Dem/liberal voters (even the ones that are more conscious etc) that read these lines will immediately smack their forehead and shake their heads solemnly at these lines. (The underlying message is not only were they too lazy to get up and vote even when they did, they throw away their votes by childishly voting for themselves or even worse, Bernie).
A final point, please don't take this to mean that I think we need some cataclysmic intra party war - that will only help the GOP. And that will only hurt the country. But people need to understand that there is an active effort by the mainstream within the party, that wants to remain more centrist and beat back the populist/progressive wave, to subtly shift blame for the loss away from the central characters and their underlying political positions. They know black voters are extremely loyal to the party; and because black voters have little to no expectations even of the Dems, they know that even if they push this narrative that if only black people had turned out in 16 like they did in 08 and 12 that we wouldn't be dealing with a pres. trump, that we are not going to turn away from the Party. In other words, we can safely be blamed without a significant loss in votes.
And not surprisingly, neither of these presumably highly educated writers have the self awareness to make the connection between the barber's statement that "no president in his lifetime, INCLUDING (my emphasis), had significantly improved the lives of black people" and why black people in states where their governments are actively taking measures to take away their right to vote and where even when they DO turnout and elect Democrats, they still feel like their lives are not improving, might suffer from a "lack of enthusiasm."