What you are saying is that they intentionally gave less information to others to give themselves an unfair advantage at mining a currency.

Spreading the currency by letting people mine it is mostly stupid. It was done in that way only because there was no other legal way. Better way would have been just to create a lot of tokens when the blockchain was launched.

As we are talking a about a currency that is intended to be used by everyone I think this would be bad, as not everyone had an equal opportunity to gain that currency.

Everybody has an equal opportunity to earn it. It's possible by writing good content and getting rewards. No other blockchain has fairer and more effective way of letting users get the currency.

And of course mining shouldn't be considered as a fair way of distributing tokens because only a handful of people in the world can mine effectively.

Also it increases centralization.

Centralization of decision making power is very important, especially when the project is still young. Steem has already made several hardforks, some of them really fast, which wouldn't be possible if it was truely decentralized.

I just wrote a post about that: How to design efficient and resilient DAO.