Strawmanning is exactly what I think Kariya is doing with this arc. Having read through so many documents for the Gourmet Notes' research, I have to admit, I do see a point to the Japanese desire for whaling (it's a bit more nuanced than that), but the points that Kariya decided to attack are kind of...poor. Non-indicative of what actual anti-whaling activists usually espouse.
As I see it, while Japan has done some fairly suspect things with regards to research whaling, the animosity they've received is both targeted and disproportionate. Several surveys have been done throughout the years that show many Japanese don't even eat whale meat in modern times, but most of them are displeased with how other nations are dictating how much whaling they can do. This phenomenon has been described as 'anti-anti-whaling', and seems to be more a reaction by the Japanese people to their perceived liberties and culture being controlled by outside forces.
Japan is no longer a member of the IWC as of 2019, and they've resumed controlled whaling in their waters. Despite this, whale numbers appear to be stable, so I can believe they know what they're doing.
I'm not putting that in the Gourmet Notes since that's just me thinking out loud.