Why would it be the end? Have any US ISPs openly declared opposition against Bitcoin? The article itself says it's strictly hypothetical. Either way, I don't think they can make a debilitating decision on Bitcoin so easily. They would have to consider what their competitors are doing, as they would needlessly risk losing their customers to the other side. It does represent a threat, albeit a theoretical one.

I don't imagine Bitcoin would be anywhere near the top of their list, but I concede that things could get really bad really quickly.