I would agree with you if we were talking about a different psilocybe, but in this specific case:

You have to eat fairly substantial amounts (assume 90%ish water, you probably want at least a gram of dry mushroom) of a mushroom that tastes awful, is tiny, upsets your stomach with indigestible matter, and you'd need to eat them in a fairly short window of time. I don't see it as particularly unlikely that we only realised here after getting it from elsewhere, the Norwegian forests have a pretty substantial list of better options.