The quote was from Nasaw's book and was therefore his selection.
Which should be enough to cast doubt on his entire premise. The guy deliberately pulled a quote that was immediate followed by the statement that educated people are the least likely to put up with bullshit. As direct a contradiction of his thesis as it gets.
The thrust of the whole passage--indeed the whole letter--is that the educated workers are more virtuous and hygienic and, in sum, that they do what they're told.
That's spin. There is no doubt the the writer is happy about the quality of educated employees, but to frame that as "docility" is to trivialize the situation. It is akin to saying that the reason people are required to pass a driver's license exam is not to make them better drivers but to make them more meek drivers.