I get the reaction, but it’s worth remembering that Japanese copyright and trademark law strongly protect creative works and registered marks. Japan doesn’t have a broad “fair use” exemption like in the U.S., only narrow, specific exceptions (such as limited quotation or educational use). Under the Trademark Act, companies also have to actively enforce their marks or risk dilution or cancellation. So while Nintendo’s actions can seem heavy-handed, they’re also legally required to defend their intellectual property to preserve its value and exclusivity.