There's a factor this research overlooked and that's intensity. Bernie Sanders won the Michigan primary with high turnout in Detroit. Those voters stayed home in November and that was the difference.
Even with the swing in Macomb county of Obama Democrats voting for Trump that was much discussed by the national media it still could have been overcome with a 2012 turnout level in Detroit. I'd be curious if that was replicated in other states.
My impression: staying home is a way of voting for some people. There are some (many?) people who have so strongly identified with one party, that when they are upset with it and want to "vote against" it, they still cannot bring themselves to vote for another party, as that seems a violation of their core identity. So, staying home is how they vote for the other party. It only counts half as much, of course. So, in this example, there might be some black voters who cannot bring themselves to vote Republican, no matter what, but if they are upset with the Democratic party they may stay home. Similarly, Christian conservatives who don't like the Republican candidate may not be willing to vote Democratic, but they might be willing to skip voting.
Just a hypothesis, of course, I have no data to back that up.
Even with the swing in Macomb county of Obama Democrats voting for Trump that was much discussed by the national media it still could have been overcome with a 2012 turnout level in Detroit. I'd be curious if that was replicated in other states.