The problem is that it is automatic, it spreads without confirming anything and without any deliberate action.
I don't believe Wi-Fi Sense is on at all by default (I am pretty sure I had to turn it on), and it explicitly shares only Wi-Fi networks you select, not all of them. You have to go in to your saved Wi-Fi networks and share each one individually. You also have to individually check each list of contacts (Outlook, Skype, Facebook, etc.)
It is absolutely not sharing all your networks automatically with all your Facebook friends.
Here are screenshots (note I'm 99% sure I turned on Wi-Fi Sense):
http://i.imgur.com/bzaK2aT.png http://i.imgur.com/vnbDkdj.png
I suppose it's ironic the FUD is directed against Microsoft now.