Assuming this story is accurate, it is a result of the electoral college system. This “white working class“ voting block is disproportionally larger in the handful of that midwestern swing states than anywhere else in the country.
A campaign based on this strategy cannot win the national popular vote. Donald Trump probably could win the national popular vote with a different strategy because the economy is doing so well and it was time to stand up to China. But he is playing by the rules.
They are bad rules for the country.