Most of the classes of jobs mentioned in this piece are not, in and of themselves, entirely bullshit. Rather, the idea that each of these people actually needs to be in the office, pretending to be continually and evenly busy, for 50+ hours a week -- that's bullshit. Work ebbs and flows in a very different way for each type of job; it is not evenly distributed across the day or week. The belief that it is leads us to create busywork, the dread and bane of all office workers.
We are struggling to unshackle ourselves from the remnants of the old, industrial workweek, which was developed around assembly lines at automobile factories. Most of us aren't building Model T's anymore. And yet, we have laws and/or employment contracts charting mandatory minimum workweeks, mandatory minimum hours per day, etc.
Some jobs really do require 40, 50, or even more hours per week. Many, and I'd dare say most, do not. Especially the white-collar administrative and "paper pushing" positions mentioned in this article. The jobs themselves aren't unnecessary (at least not in reasonable quantity), but the idea that all jobs are normalized around the same schedule is absolute lunacy.