Community Forum
The xfinitywifi can be disabled from your online account page.
To turn off the public hotspot, go to
http://customer.comcast.com/help-and-support/internet/disable-xfinity-wifi-home-hotspot
https://www.xfinity.com/support/articles/hide-disable-in-home-wifi
I've seen it mentioned elsewhere that even if that page shows it disabled, sometimes you need to enable it, wait a bit then disable it again to get the public wifi to shut off..