> As much as I loathe the "facebook is a private company that can do whatever they want" argument, I have to admit it applies here. If I owned a store, and some guy kept coming and showing customers how to not spend any money in my store, I'd kick that guy out of my store.

Saying he "came and showed" implies he was doing this on Facebook, but he was publishing a Chrome extension. This is more like McDonalds blacklisting you because, in your job as a nutritionist, you gave people strategies for reducing their fast food intake.

It's a browser extension, not Facebook itself. They banned him for showing other people how to do something on their own computers.