Consider Disney.com. Nothing new or hip about it. I'd bet >80% of the users are under 30.
I think this is a fairly incorrect assumption, and it feels like it's being used to justify an opinion about Facebook here by undermining how "cool" and "hip" it is.
Just come out and say what you want to say. Facebook sucks, and there's definitely nothing new about it anymore. I'll do you a favor and not try to trick you into agreeing with my opinion by making misleading correlations between it and objective data. If you disagree with me, awesome, you've found something of value in Facebook. That's great for you. I hate it. We're different! :)