The root cause of this denigration is blue collar work is neo-liberal hegemony.

The Anglo disease Jerome postulates provides a plausible explanation of why economies unbalance themselves. So to my mind, the decline in the status of "blue-collar" work, which is quite likely a consequence of (and certainly parallels) the decline in and, yes, denigration of manufacturing since the 70s, might very well be down to an early manifestation of the Anglo disease, i.e. neglect of manufacturing in favor of an easy-money "service economy". (Further contributing factors include the lack of effective unions and of unified vocational education standards.)

In a country like Germany where manufacturing is still considered important, having a qualified industrial skill remains a pretty reliable gateway to a "middle-class" life; those individuals without a trained skill (not counting university-level education of course) are regarded the way HS dropouts are in the States. So in that sense a lack of education does indeed seem to be eroding the opportunities of non-college educated Americans.

This is key, because based on present evidence broad-based prosperity seems, based on present evidence, most likely to emerge out of, and be sustained by, a broad and sophisticated manufacturing economy that demands sophisticated industrial skills.

So instead of going on about blue-collar/white-collar, Sirota should be asking how to re-industrialize America.

There: I've finally put my finger on what's been bugging me.

The fact is that what we're experiencing right now is a top-down disaster. -Paul Krugman