Reminder: Facebook (and Twitter, and ...) is NOT A MONOPOLY.
You don’t have to use it. There are plenty of alternatives. Just because your friends are on FB doesn’t mean you have to, or that you have to use it a lot, or that you have to use any of the many tendrils it puts out into the world. I use FB proper to track generic friends; refuse to use the rest of its “services” like “FB sign on” or Instagram. There’s plenty of elsewhere to be, and the reduced usage reduces what they get out of the project.
There’s much more to the Internet than Facebook et al. You DO have alternatives.
It’s a monopoly. Other oil companies existed when standard oil was broken up. Other phone companies existed when the Bell System was broken up. When one company has such a dominant share however, they are a monopoly even if they do have a few minnow sized competitors.