Facebook is a bit like going to Mexico. Actually, it is exactly like going to Mexico. There are some that venture over the border despite all the warnings and find it an interesting and delightful place. There are others who have never ventured anywhere and don't intend to, but who nevertheless issue dire warnings to the rest of us. There are the unfortunate few who have never crossed into Mexico but who crash and burn back in their own country AND of course there are a few who do cross into Mexico and crash and burn there.
Same with facebook. You can choose to expose yourself to the world if you are particularly stupid or inept, or you can configure things so you can maximise the benefits of facebook while minimising your exposure. Your choice. BTW there are nearly two billion users who get on facebook in any month so obviously the "don't go to Mexico or you will die" scare tactics aren't working