In what sense did Facebook ‘happen’? People chose to join; they weren’t forced to. Facebook qua social network is a valuable tool for many people.

Now you can perhaps make the case that their effort to monetize was an unethical bait-and-switch. Get people on the service, then keep them engaged via promotion of provocative and unhealthy behaviors, which ultimately fuels an advertising money-printing machine the likes of which we’ve never seen before, save Google.