Actually I think he does believe in a "more open and connected world is a better world". Here is an acid test to see that it is true.
Facebook is investing a huge amount of money and resources[1] to connect the world. You may think that they do it only for money which is fair, but as Zuckerberg said on Bloomberg[2] there is not a lot of money to be made, if not at all, by fighting to give internet access from mid to poor countries. " If we were primarily focused on profits, the reasonable thing for us to do would really just be to focus on the first billion people using our products. The world isn't set up equally, and the first billion people using Facebook have way more money than the rest of the world combined. So from a biz perspective, it doesn't make a whole lot of sense for us to put the emphasis into this that we are right now. "
Even if he does it only for money, what he is doing will only be profitable after more than 10 years. And the profits won't be exciting because of the poverty, the small growth of these counties, and their capacity to have a better GDP per Capita. With $15 per day what can you do with that? And with this total amount to be spent how can you have any CPC being not close to 0? It will be better for these people in 10 years maybe or more but, not now unfortunately...
So his mission does seem to have a more open world and to connect people first. You have more in the interview.
[1]https://internet.org/projects
[2]http://www.bloomberg.com/news/articles/2015-02-19/mark-zucke...