The way I look at it....
If I buy something, I should get what I pay for. Period.
If I buy a car, I expect to get what I pay for.... buy a fridge, same thing. I under stand the necessity to shape traffic and I can ALMOST buy limiting bandwidth under the most EXTREME conditions. Limiting bandwidth based on protocol is not only wrong, for something that was sold as "unlimited, unrestricted" access it is actionable in the US Court system.
I ~AM~ a Comcast customer.... do I get what I pay for? You betcha, in spades. I pay for an 8MB connection, and actually get 25+ MB. How did I get it? Calling and complaining when something wasn't right. Modem dropping offline? Call them. Slow ass speeds? Call them. Make coming out a weekly (if not daily) thing. EVENTUALLY they will fix the issue (and apparently in my case) take the pad off the line. And no, I have detected no decrease in BT speeds, I suspect in part because I bitched so much they don't dare touch my line. Crappy lines in my area? Was a daily call until they strung new cable. Blasting port 53 on my router trying to "discover" an internal server in my house? Threat of legal action... never got hit again.
There is no reason why everyone can't have an 8 to 12 MB connection to thier house running at full bore. Don't bellyache about capacity. There is soooo much dead fibre strung right now it sickening. And for every one high-bandwidth user there is, there are 4 "grannies next door" who are so far below the maximum threshold it isn't funny. If 20% of the users are saturating capacity, then there is a serious issue with their capacity.
Voting with your feet only works if EVERYONE stands up and walks out, which isn't going to happen. The true people who are effected are the high bandwidth users, who, by and large do not want to reveal the reasons for their high usage. Guess what, doesn't matter what you use the bandwidth on. Call and complain.... repeatedly. You will get results.
I will leave you with one final thought. Never, ever, ~EVER~ take NO from someone that can't tell you yes to begin with. If you get "NO" from some script reading loser on their tech support line, keep escalating... repeatedly if required. This applies to everything.... not just Comcast.