I am struggling a bit to understand how Comcast could not argue that it is required?
I don't fully remember but I don't think I started paying anything for my service until someone came out to install when self install wasn't an option. (I could possibly see them justifying removing self install in the name of retention later, since how many people really have a choice in their ISP and will just not deal with waiting for someone to come?).
If service was unable to start until someone came out, to me that could be argued as part of the sign up process.
I am not necessarily agreeing that it is part of the signup process. But we know that these companies love their shady practices and will have their lawyers finding any loophole they can find.