For those of you who aren't fans of FB but still want to be involved, I'd recommend building a 'burner' FB account and use it exclusively for the gaming groups.
I tried creating an account just for gaming groups as I don't want to be generally 'on facebook'. I joined a few groups and acted as a normal member. i.e. I posted pictures of my miniatures, made normal comments, liked other people's efforts, made figure suggestions, linked to my blog but nothing spamming, offensive or weird. Everything was fine for a few days, I got lots of positive replies and I even got assigned a rising star status on one group for having received lots of likes.
Then FB locked my account, saying I hadn't complied with their policies. I think my crime was to not use my full name. In order to appeal I had to submit a picture and my telephone number, which I wasn't happy with but stupidly did as there was no other way to contact them. They never replied and I never got access back to the account to delete it. Keep well clear is my advice.