You are making an inference about Ruy's politics which is inaccurate. He's a friend of mine, so anyone can take that any way they like. (correct spelling: Teixeira. He's of Portuguese extraction, fyi.)
For Ruy the attention to white workers serves the purpose of forming a complete notion of class. It's not that he sees them as some crucial vanguard of change in and of themselves. They are conspicuously absent from Democratic voting rolls, but that goes to the Democrats' failure to address class. Ruy's point is that the Dems have traded white workers for "suburbanites," and pocketbook class issues for their stands, such as they are, on things like choice, gun control, and affirmative action. I think there's a lot to this, as could be gleaned from my posts.
Ruy is pretty data-driven. I don't believe his results are biased by his preconceptions.
mbs