> I'm saying someone else would fill Facebook's role whether it's evil or not. Do you disagree?
History says you're right.
There were many similar sites before Facebook existed, including Friendster and Google's Orkut. You might also count MySpace.
There have been a few attempts to replace Facebook, the most obvious one being Google Plus.
Typically, due to power law effects, technologies end up with a dominant supplier: there's only one Amazon, one Google, one Wikipedia, etc.
Given that Google is already dominant in search, email, online video (YouTube) and mobile phones, there's a case for defending Facebook as the lesser evil...