Funny, my experience is the opposite on literally every concrete assertion about people and motivations.
Looking at my team, and the broader team under my director, only one was hired "straight out of college". Well, if you consider fresh PhDs to be "straight out of college", there are a few, but I doubt Aaron meant folks approaching 30 with kids on the horizon when he was talking about people just out of college.
Perhaps a couple are cynical, but I wouldn't call any childish or enthusiastically adolescent, which isn't too surprising, considering that the median employee within two levels of management of me is mid-thirties with two kids.
We have a couple of visiting scientists (professors at major research universities), and they were surprised by what we're doing, so perhaps the secrecy doesn't do such a bad job of keeping things inside the company after all.
I don't doubt Aaron's experience, but it's exactly what you'd expect due to selection bias. How old was Aaron when he wrote that, 20? He probably wasn't hanging out with the median person from my team. There's nothing wrong with that. But, all things considered, that essay contains a lot of awfully strong assertions.