It is interesting that the meaning of"jerk" has moved very recently from meaning something like "bumpkin" to something closer to "arsehole". As the author points out, this is similar to the change in the meaning of "villain", along with several other words where a class-based insult eventually became moralised.

But most of the words he mentions are old words that changed their meaning back in the days when litteral aristocrats, kings, dukes and princes ruled the English speaking lands and their neighbours. "Jerk" changed recently and I wonder if the change hints at a new class system.