How you interpret the 2016 election is, so far as I can see, a reflection of whatever previous bias you wish to confirm. Like reading the Bible, there is plenty of support for whatever point of view suits you best — and like Biblical interpretation, it’s all about gaining the moral high ground (and more importantly, punishing the apostate).
It’s doesn’t do you a lot of good to simply point out the racism inherent in the Republican base. This has been the case for a long time, and it doesn’t explain why 2016 was different from 2008 and 2012. This is a particular limitation of the whitelash narrative’s explanatory power.
Trump’s win cannot be explained by the behavior of traditional GOP voters, since their voting behavior has not changed. His 306 electoral vote total masks a razor thin majority in the industrial midwest states that previously went to Obama. The well-to-do base the article cites did not create the Trump presidency — rather it was defections from working class voters in the rust belt. In an evenly matched political contest, the marginal vote is the deciding factor.
So are the white voters of the industrial belt racist? Yes, but that’s not really the operative question. The real question you are not asking is are they more racist than they were in 2008 and 2012. If racism is your explanation of Trump’s win, then you are obliged to explain why this racism reared its head in a contest between two white geriatrics rather than in the two elections that feature an actual black candidate.
The obvious purpose of the interpretation offered up by this article is to reinforce the dominance of the center-right Clinton/Obama axis, and to marginalize the resurgence of the progressive wing. “Engaging with Trump voters” is code for the blocking the debate over economics — a discussion the party is unwilling to have.