Oh, shut up already. Not everyone is a 45-year-old neckbeard troll living in their mom's basement with greasy Doritos hands and Mountain Dew stains on their shirts.
I know and like my friends since before they joined Facebook. It's outrageously unreasonable to suggest that I ditch them now because they have an account on a website. Surely they don't expect them to judge me on having an account on /.
Facebook allows us to communicate on some aspects of our lives, perhaps today most commonly through sharing pictures, much as people used to do with postcards and snail mail. It isn't meant to replace face-to-face conversations. There may be something to be said about people who exclusively rely on Facebook, or who share TMI. But instead of ranting aimlessly like an old fart, I just unsubscribe to their feed.
Not everyone can afford or is willing to end friendships based on social network memberships. Facebook's success in particular and the emergence of so many networks in general are evidences to that. Your dogmatic view on social relationships is neither correct nor necessary nor relevant nor required.