Ironically, waging effective war on them would probably involve not defacing their sites (which I imagine would only make them scatter) but instead infecting them and then handing the c&c server details over to the authorities, who I'm sure would proceed to monitor everyone visiting the sites and then making the actionable creeps truly miserable, as only large, well-funded governments can.
It would be super trippy to see entities like Anonymous and the US gov't collaborating.