I think the point is that they're trying to force communication patterns from FB into email. Just because they're both social media doesn't mean people wish to communicate the same way on both - different affordances lead to different behaviors.
Yep, and I'd say the masses, who only really came to the internet with the advent of web 2.0, only know how to do social media the new way, not the classic way.
Even technical users seem to want to move away from email for more than office communication and password resets. A lot of projects move off mailing lists and on to forums, issue trackers, etc. because the affordances just match modern expectations.
