Xfinity includes it in their new Wifi router and presents it as a feature:

https://www.xfinity.com/hub/smart-home/wifi-motion

You also are not able to run your own hardware, you must use theirs. This is why I canceled Xfinity on the same day they installed it, after discovering this.

If you're willing to fortify your network in terms of security, I highly recommend building yourself a WiFi router or just buying a highly customizable one like MikroTik or alternatives as such. I think its easily the best defense for such cases.