Good point, but then again, of course there are limits and you should know how to use these limits.
Privacy is very important and I pretty much understand your point, but the good thing on FB is that you can also control your Privacy, it's tiring no doubt but useful. Also, If I have to pick up my phone and call for example my two sisters, my parents, my friends whom are all away from me, then I'd be broke in just 1week.
As for your last part, I'm 100% with you there. Couldn't agree more.