The ironic thing is that he lists monetization last, but simply by uttering that sentiment he tells us that they are really thinking about monetization first, aka the end goal of the product.
Even if he didn't say it, it's implicit in who they are. Do you really think a massive social media corporation is going to launch another social media platform, just for funsies?
No, no, just pointing out the blatant contradiction in the statement. Although I do wish an app intended for a billion people had a component of goodness to it!
I don't think he's ever suggested Facebook is anything but a for profit enterprise, but I think it is an extremely cynical take that "build a product a billion people would use before thinking about monetization" actually means "think about monetization first".