If you use Facebook the old fashioned way (an actual network of friends) it's probably very pleasant. If you start joining "Groups" which are similar to subreddits, it's the most toxic thing I've seen. I never really was a real Facebook user with a network in the first place, but one day on a whim I went to the FB site where I still had my account and decided to join some random suggested groups. That's where it becomes toxic. Everything becomes incendiary things about the US president and usually further devolves into trolls saying openly racist things, there's no moderation and it's a real cesspool. And I'm talking about groups dedicated to hobbies and cartoons.