True; there are lots of trouble-makers, extreme groups, spammers, scammers and even worse there, but there are also pearls, useful links, news and treasures of pictures, ideas and knowledge waiting to be explored.
I would say that Facebook is a wonderful tool that has been misused and misunderstood by too many people with varying views and aims - on purpose or by accident.
That does not mean that it is bad; it means that you have to take a closer look at things and "separate the wheat from the chaff".
There are still lots of good people there - you simply need to discover them, by taking some precautions, of course.
And - a huge, too sophisticated "metropole" might be worse than the normal jungle ...