Japanese game companies are a lot more protective about their IP. Nintendo is simply consistent about that in the West. To them it's quite normal to exercise a lot of control over how your work is presented in public, which includes things like tournaments, emulation, fan games, mods, and so on.

A Japanese Youtuber was arrested for posting spoilers of a visual novel: https://www.gamesindustry.biz/japanese-authorities-make-thei...