Facebook isn’t a mind-control ray. It’s a tool for finding people who possess uncommon, hard-to-locate traits, whether that’s “person thinking of buying a new refrigerator,” “person with the same rare disease as you,” or “person who might participate in a genocidal pogrom,” and then pitching them on a nice side-by-side or some tiki torches, while showing them social proof of the desirability of their course of action, in the form of other people (or bots) that are doing the same thing, so they feel like they’re part of a crowd.