Being that I've worked in higher ed for 4 years now, I'd say the authors are pretty much nailing it. The only place I part company with them is on the level of danger the practice has as it stifles free expression not only on the campus, but in the areas that surround it.
However, there is a shining beacon in all this--some bright entrepreneur could make a fortune by starting a service to aggregate the names, any publicly available identifying information (schools attended, hometown and so on) and publicly available spewings of these twits into a subscription database. Potential employers could use it to search for applicants that they want to weed out of applicant pools at hiring time.
I don't think "self-righteous arrogant ass" is a protected class yet.