Due to the nature in which they are (supposedly) interfering with traffic, many have lashed out at Comcast, claiming their tactics are outright unethical. The issue is cooking up so much, in fact, that now Congress is getting involved. One particular Representative, Rick Boucher, is petitioning Comcast to stop any filtering they are doing. In fact, he claims that stopping torrents or other peer to peer traffic is actually harmful to the Internet.
This all comes back to issues of net neutrality and how where the actual responsibility of quality of service lies. The Internet, as a relatively open medium, is largely successful because of how versatile it is. Access restrictions, no matter how big or how small, are a small precursor to a world in which nothing is free. The article is an excellent read about the situation as a whole, and does bring up excellent points on how the Internet itself might grow.