My view is that there's no harm in indulging this power fantasy if it's just a game, but when you try to merge it into your everyday life, you're playing with fire. Secrecy begets exclusivity and intentional power imbalance, and society as a whole needs less of both.
It was seemingly a large art project. Some people were "in the know" because projects like this require the full time work of several people. You exclude as many people as possible because it ruins the illusion that people enjoy. Your post may as well criticize Disney World for being a power fantasy because they don't allow park visitors behind the scenes.
Frankly the way that account is told more than explains why people were distancing themselves from him or her. (S)he sounds crazy.
You have to admit, though, that being handed a mysterious invitation by someone who refuses to tell you more is the closest thing you'll ever have in real life to getting your acceptance letter to Hogwarts. Even capturing a small amount of that magic and excitement is pretty cool, if you ask me.