In Japan let's say there are Big Bosses of law firms called Big 4. They can even make Jesus punished by death penalty lol:
https://en.wikipedia.org/wiki/Big_Four_(law_firms)
So Nintendo has an army made of Big 4 and some global ones that are master at their own areas as in which part of the world they tend to operate. You can run but you cannot hide lolol.
Yep. Top 1 mistake pirate communities does is asking donation. It ruins, let's say "fair trade" laws among many because you make money from something you don't own but someone else owns it. It's like stealing in the eyes of the law. That's why Yuzu emulator legally got easy to kill.
However, law cares about severity of how many laws broken and how. Yuzu broke many laws beyond making money from the emulator which is strike 1. For example no one is allowed to ruin protection systems of video game consoles but Yuzu does to run the game so this is strike 2. Yuzu was publicly shared tool that breaks protection of a legally protected device which is strike 3. Emulators trying to keep "legal" by making itself useless unless you need a file or something from the console, however it does not help at all. Nintendo stated the fact that Yuzu emulator doesn't care if people use pirated or original game, it had no pirated content check so they used this fact that Yuzu allows piracy and became a common tool that caused Nintendo to lose sell so it's strike 4. In baseball 3 strike is enough for strikeout but there is at least 4 strike here lol.
Thus emulators are beyond in legal grey area anymore, they are necessarily illegal but to make a case out of it company require to prove if an emulator is so popular that they lost sell so legal system can care about this evil crime lol.
However what emulator can be legal so even Nintendo cannot do anything?: Emulator shouldn't break protection system of the console and emulator has to have strict check on being able to understand if a game is pirated or not. So long story short, emulator doesn't use a file from the console, it does not break protection system of the console and/or the game and you can only play a legal copy of the game. But since consoles uses protection systems it makes it impossible to not require at least a file from the console and emulator can run the game without breaking protection systems that's legally protected.