It is easy to explain the whole story, conspiracy-free, from USA Today, September 2012:
Part of the explanation is in the socially conservative views that many of these voters have on issues such as abortion, gay marriage and gun control. And a small, but hard to measure, part in this election is lingering racist attitudes toward the first black president.
But much has to be attributed to how the Democrats have taken these voters for granted. Eager to win the growing immigrant vote and to push liberal causes that many workers view with indifference or hostility, many Democrats have come up short in addressing the declining standards of living that have hit the working class through decades of losses in manufacturing jobs. More.
Reality check: From what one can see, progressives do not live in a world where ordinary facts matter.
We can expect many more overripe and rotten theories for a long time before they come to terms with simple error. They will then abolish independent analysis.
See also: Is Trump derangement syndrome about something bigger?A sense that the world isn’t just tipping over indefinitely into mindless and violent progressivism?