MS decided that its a good idea for your Facebook friends and everyone else to have access to your wi-fi password.
That is dumb
They decided it's a good idea to give you a mechanism to share it with them if you want to.
The password sharing is done via a service provided by MS that both you and the person getting the password have to go sign up for.
This "feature" may not make it into the final release, but if that's your reason for not upgrading then you're basically saying it shouldn't be in there because you can't be trusted not to shoot yourself in the foot with it.