Are personality traits substantially heritable in general?
Do the offspring of families with patchy or zero employment histories typically select mates from similar backgrounds (or are they likely to be shunned by those from other backgrounds?)
Are those traits (whatever these traits actually are) also heritable?
I don't know the answers, but the guy who wrote that book is Lecturer in the Neurobiology of Personality at the Institute of psychiatry, Psychology and Neuroscience, King's College London. He might. He also appears to have claimed the dole before getting the science gig
so maybe he isn't an evil elitist.
Generally it is wise to avoid politicising science this way.
Better to just work out whether it is correct, or else discover the error, and move on without resorting to sectarian hatchet jobs.