The URL in this case is harmless as it is the infected users hostname.
Far from it, the bots use their own host to serve their virus to others to make them harder to shut down, do some nasty things with the http replies (such as giving seemingly innocent extensions a hostile Content-Type) and appear to be more authentic (where else would the user be hosting *their* webcam, on crappy geocities?).
Advising people not to click links that are advertised to them is a good idea, telling them a spammers/trojans own hostname is harmless is not.