Any effective advertising is mind control, in a sense. It convinces you to take an action you wouldn't have otherwise taken. Sometimes that action is bad for you, but the advertising has convinced you that it's good for you (or that the alternative is scarier).

The better Facebook can convince you to take an action, the more value its platform has. The Darwinism of the ad industry meant that the top ad-tech companies were eventually going to be really, really good at changing people's behavior.