Well, taking down Paypal and Visa after they stopped processing Wikileaks donations didn't "help much" either. But it is some form of protest after all.
Note that they did not give WikiLeaks their money back nor lose a lot of money.
I agree it's a form of protest, but not a very good one, because it paints WikiLeaks / Pirate Party supporters in a bad light, and having public opinion on our side is more important than taking down a few servers for a few hours.
I agree that this could be bad PR for the Pirate Party. But then Anonymous is not the Pirate Party and their goals don't necessarily line up. The way I see it, Anonymous' actions are usually less demonstrations for a particular cause, but more against certain violations of civil rights. In the Wikileaks case e.g. I assume that not everyone who participated in the DDoS against Visa, necessarily agrees with the way Assange leads the organization or cares much about Wikileaks success. And that's probably similar with the current case. You're sailing in the same ocean, but you're not all in the same ship.