I don't think they got as much PR as you give them credit for. I suspect most people don't even recall this story if they even bothered to read it in the first place.
Whalers, anti-whalers, divers, animal rights folks, etc are talking about it. In otherwords, the same group that were already informed that whaling was still going on.
Not too mention as well that the OP to this idea assumes that sympathy would lie with the Watson Gang. I think more people would be taken back by the activities of pseudo-pirates and eco-terrorism.