The critics rarely know today's circumstance in Japan. I've eaten a piece of Whale mea only one time for twenty years, and in only a few restaurant whale is available. The clear thing is, whale meat is no longer eaten in everyday life. Come to Japan and you'll agree to this point.

Anyway here we can see Greenpeace bases on "preservationism", not "conservationism". That is, whatever protocols around the whale use is and however the whale is used, they rationally disagree with killing whales itself.

In this case, the interference of preservationist like NGO is thought to destabilise the whale regime, since this regime aims to establish the sustainable use of whale. Unlike Greenpeace, on the other hand, another NGO like WWF is thought to support this regime because they're conservationist.

Same thing had been seen in CITES, Convention on International Trade in Endangered Species of Wiled Fauna and Flora, aka Washington Convention, especially from, I remember, COP8-9.