To me, at least, there's a difference between information I willingly, if unwittingly share on a social network vs having the government unwittingly and unwillingly collect information indiscriminately. Furthermore, Facebook, Google, et al do not have SWAT teams that can be sent to smash open my door and flash bang a baby based on what they find.

I'm not saying I think it's good that private companies collect all of our data (and personally the info a CC company has creeps me out far more than FB or Google), but I can choose to stop using their service and greatly minimize the amount of data they receive. There's very few caves in the world where you can hide from the US Government.