I was wondering when they'd start doing this one. Many of the attacks were done using a program called "low orbit ion cannon," essentially an opt-in botnet: run the program and it waits for a signal from a master node, then starts spamming requests at the specified target. Meaning that the participants in the attacks, far from the usual unknowing and unwilling infected, were in fact choosing specifically to join in the action. What's more, the nature of a DDoS makes proxy use counter-productive and ineffective (all attacks come from a small number of proxy IPs, being easily blockable, and you DDoS the proxy long before the target).
The end result? A list of unprotected ip addresses for a bunch of idiot thugs and 13-year old kids, not at all anonymous. Well done, geniuses.