No...it's anti-anyonebutnormalcustomer behavior. The people running dns servers are probably 0.000001% of internet users....the rest are probably just infected machines.
The question is *why* do they care about filtering DNS traffic? Do they offer this service as a paid service elsewhere, costing them *money*? Or is it simply to try to get a handle on worms and malware, which uses tons of bandwidth for a network as big as comcast, costing them *tons of money*.
They have a profit based mindset...it shouldn't be hard to figure out why they're doing it. If the cost from malware is more than the loss of a portion of a fairly insignificant customer base that in reality probably costs them what several regular users cost, then they'll choose to block the port!
At one point I called support and asked what kind of account I would need to legally (in terms of usage agreement: no servers allowed) run a website. They said I'd have to go elsewhere to a *hosting company*. That's probably what they'll tell you here.
I think as much as we complain, in the end, if you want a direct and unfiltered, higher risk, and more expensive to maintain connection to the internet, you'll have to...pay more....just like if you want to use 5x the bandwidth of a normal user, you'll have to pay more.
I like the idea of the internet being a standard connection, wide open and the same anywhere...but that's not going to happen without regulatory laws, cause it doesn't make much business sense.