I mean, you were being a bit condescending? You're also quite wrong, in that you define "friendship" in a very strict way that doesn't comport with how other people use the term. It's quite possible to have friends that aren't close friends; people whom you have fun with, whose lives you would prefer to be able to know something about, but whom you wouldn't go out of your way to keep up with if it became inconvenient. These people still count as friends.

To put it another way, I have family I would lose touch with if I left Facebook. They're still family and I would still prefer to know if they graduated college or got cancer or died. Same with friends-who-aren't-close.