This is a response to a bunch of the TL;DRs I've seen.
He doesn't resent the people he mentions in the article because they're happy or having fun. He points at specific behaviors and elements of the culture that he doesn't like and gives examples. The fact that so many have a knee-jerk reaction to this article, rather than a thoughtful one, serves his argument. At some points in the article he does come off petulant and young. He probably is young. But in other places he has good observations about some distasteful peculiarities of the culture. For example, he brings up the delusions-of-grandeur-like advertising for an event called, "SuperHappyDevHouse." The state of the culture is not a frivolous issue. A lot of smart people can be pushed away from CS if the culture isn't right.