I smell astro-turfing
While this doesn't exactly qualify as astro-turfing, I'd say that if a user using Bit Torrent for the first time finds that Comcast has started forging RST packets to throttle traffic, then this isn't a "reasonable network management" procedure, but discrimination.
It is a given - and Comcast has admitted to it - that they bill their service as "unlimited" and also sell it as such but secretly cap the bandwidth at a given point. And they refuse to give any real specifics on this cap.
Now they have been caught forging RST packets - pretending to be both ends of the connection - which could be in violation of the laws of several states. Not only that, it is highly deceptive, since they apparently do this to several different types of traffic regardless of whether or not the user is close to the "secret" bandwidth cap.
And Comcast has admitted that they do provide favorable service to certain types of traffic. IIRC, in one of their statements about their practice of forging RST packets to halt Bit Torrent and P2P traffic they stated that this was done to ensure that Gamers have a stable connection. (Yes, those gamers - the ones who will spend excessively large amounts of money to buy a system that will give them absurd frame rates that are so far beyond what the human body is capable of perceiving it's sickening.)
The real question is: Why is Comcast discriminating against P2P traffic? Answer that question and you're a step ahead of most people disgusted over this obvious, blatant discrimination. I, personally, believe it has more to do with "Corporate Culture" than anything else. Gamers and the Average 'net user don't, really, use all that much bandwidth on average, so they will never run into the secret bandwidth cap, and because of Comcast's promise of "Speed Above That of DSL" they will gladly pay the premiums for the service. So the corporate behemoth sees a massive profit in catering to them and doing what they can to ensure that their "favorite" customers remain "Happy Sheep". What do they care if "a few Thieves and Geeks" aren't happy?
Thanks to the US Supreme Court decision that Cable Companies are not "Telecommunications" services, therefore exempt from the "line sharing" rules that Telecom companies are subject to almost every major area is locked to one of the major Cable providers or to a the company that has a regional lock-in. And since this places major limits on the choices people have that means that either: 1) Going to an internet service without the bandwidth they've grown accustomed to or 2) Staying with the service they are dis-satisfied with. With most people not willing to switch to a service that has less bandwidth there is no reason for Comcast to stop the discriminative practice of severly throttling Bit Torrent and P2P traffic.
So the discrimination is almost entirely monetary. However there is another facet to the discrimination - that the Corporate Culture has the view that all P2P and Bit Torrent traffic is for illegal, copyrighted content. (And the stuff that isn't illegal, like most DVD images of Linux distributions, is limited, fringe content and it doesn't matter if it gets blocked)
In the end it comes down to it being nothing more than making money and, well, stupidity.