I've lived in the UK for about 10 years now and though I'm not sure I read or picked up this idea, it has felt "true" in a truthy sort of way - the UK, culturally, regards software engineers or those similar to be little more than educated manual labor. You're not in management, so you're labor. It's a result of the significance of "class" here in the UK and the different ways to define that. And "middle class" here is roughly the equivalent of "upper middle class" in America and IT folks don't make enough to be in the "middle class".

"Lions ruled by donkeys" - this saying about British society is still true today and has its roots in the class divisions and structure. I have heard it said many times by now that Britain is still fundamentally a feudal society, certainly on the psychological level. (And I can see it) So that is going to certainly influence what management pays labor...

It has made me very appreciative of the strengths of American culture/society, though there are lots of things to complain about America as well.