Well, the nuclear regulation authority in the article is a department in Japan’s government, presumably at least somewhat beholden to politicians and therefore TEPCo and other businesses as well. Do you have info on a non biased organization which corroborates their conclusion?

Again, it may be completely safe, and probably is. But the reason the”solution to pollution is dilution” was used as justification for waste disposal while creating horrible environmental disasters is because each individual polluting act is just as they say - essentially harmless to the environment. It’s the consistent release of pollutants over a long period of time which destroys the environment, and it’s been 12 years since the tsunami, and this is hardly the first irradiated water they’ve released.