Facebook serves a purpose for many of us, despite the obvious damage it’s done to our society. It may be hard to go cold turkey right away but there’s an interim action that will have an effect if you need time before pulling the plug.
First, scrub your personal data off the site as much as possible and restrict your permissions drastically. This is just commonsense safety and shouldn’t damage the funcional social value to you of using the service. If you still want to see photos of your little cousins and see updates from HS friends living far away, you should be able to.
Second, employ the strategy that’s been so effectively used by Sleeping Giants: Click on the ads you see and write, “I won’t buy any product advertised here.”
Facebook sells ads. If the advertisers spook, the company takes a hit.