This whole suit is completely nuts. Huge increases in power usage? From a device that at most uses 50W (and probably only when charging an empty internal battery)? Does that household's electrical appliance inventory consist of one LED light bulb (and no computer)?
The hot spot is not public. It's open, security-wise, but all you get is a login web page. You have to log in with your Comcast subscriber info to gain access to anything. It shows up as a distinct SSID ("xfinitywifi") from the customer's own.
Whether you agree or not, Comcast advertises it as a benefit. You might share some of their bandwidth going to your modem with others, but you also benefit from being able to use the feature when you are away from home. At least that's the theory; I've never even bothered to look for it, as I have tethering on my phone and just use that when I'm not around free Wi-Fi spots.
I do have Comcast service and they enabled it on my (actually their) modem. If I hadn't know about it (from Comcast advertising) I'd never even have known it was there, it would've been just another mystery SSID popping up. I suppose I might notice if someone started pumping gigabytes of bandwidth through my connections, but that's not likely. I'm not located in a dense urban area, so someone would have to be parked in my driveway or visiting my house or my neighbor to actually use the capability. So in that regard I don't care that it's turned on, and if I have a guest that wants to use it, then that just means I don't have to give them my own guest access keys.
So for me it's really a no-op.