There are a lot of people who share fractional responsibility for Trump's win. Yes, black voters who stayed home are among them, but they're waaaay down the list, which starts with the people who actually voted for Trump, and arguably comes after the people who insisted running a candidate that was loathed by a large portion of the electorate. It also includes Comey, and Russia, and Republican candidates that did a shitty job, and media outlets that did a shitty job, etc.
The election was close enough that you can point to a dozen different things that -- if they'd shaken out differently -- would have changed the course of this disaster. But they didn't, so now we have what we have.
I'm not sure this interminable pointing of fingers and navel gazing is particularly useful in general, but specifically if you're pointing to a single thing and decrying it as the sole reason Trump won, you're full of shit and missing the point. There are dozens of things, if done differently, that can have a significant effect. This idea that we need to find the singular cause of our failure and then browbeat anyone who disagrees with us on it is wasteful, divisive, and just ignorant of the facts.
In short, turn around, quit looking at the ass-whoopin you just took, and start doing something to avoid the next one. Multiple somethings, even. Try actually addressing black issues if you want more black voters to turn out. Address rural whites if you want more rural whites to turn out. Run a candidate whose negatives aren't in danger of overwhelming their positives if you want people to get excited and turn out.
At the beginning of this campaign, I repeatedly attempted to get posters here to quit treating the different wings of the Democratic party as if they were the enemy. I was a dismal failure on that front, because apparently it's just more fun for you guys to hate each other and call each other names than it is to acknowledge that you have more common ground with one another than you do with any other available party. Again I say, get right with each other if you want to get right with the electorate. Understand that there are multiple paths to victory, and there's nothing wrong with pursuing them in parallel. It's fine to reach out to black voters and it's fine to reach out to white voters. We should be reaching out to every fucking one, because that's who is going to take a fucking from this administration -- everyone.