> The main unifying aspect that the "filter bubble" criticism and the "connecting people" criticism seem to have in common is that both involve Facebook taking away some control of the culture from the press, the media, and other powerful groups and giving it to the populace

No, it's giving it to a new powerful group, specifically, Facebook. Just as Stalin stated, “I consider it completely unimportant who in the party will vote, or how; but what is extraordinarily important is this — who will count the votes, and how,” so, too, is it true of social media; power doesn't lie with the people who can press “Like” (etc.), it lies with the people who select and continuously tweak based on observed effect the algorithm by which Likes and similar actions are used to shape the flow of information to and between users.