i guess his point was that the reason the web works at all, or tcp/ip, or email, or any of the really successful platforms - is because of certain contracts of openness and (essentially) fair play that are built into the very structure of how they are built.

this openness allows them to scale to that level and without it you can't get to truly global scale.

Please re-read the line, there is a but before "on a deep social and ethical level, Facebook and its platform are not web-scale".

I think he meant for any company to be web-scale there are other sides of the story included too - having big, distributed data centers alone is not sufficient. There is a thing called "privacy" and "trust" which would scale throughout the internet, for which Facebook never had serious concerns, IMO.

I think he means that gatekeepers are a step down from the web, which is not censored.