All those mediums have one thing in common - a degree of personal privacy. Why I would want to put my life online via so-called social media for lots of people to cogitate over, is something that to date no one has been able to provide a cogent explanation for.
You sound like someone who hasn't spent enough time with the medium and took a look to form your own opinion. How much you share and with whom is entirely up to yourself. Facebook can actually be a very nice way to stay in touch with people that live far away, and it can be a really nice addition to everything you do on the phone or by email. It's not all "look I'm on vacation in Florida and having a 1 litre mai tai!" kind of thing.
I use it to stay in touch with study friends who by now live all over the planet, and my wife is member of a group of mothers in Amsterdam that exchange very worthwhile tips about parenting etc.
So, again not trying to convert you to a Facebook user, but the way you approach this is a bit in the "get off my lawn" league.