I canāt say Iām overly surprised - everybody knows the unspoken rule in the murky world of console emulation is ādonāt mess with the currently supported generation and youāll largely be left aloneā, so Iām surprised both of the big names in the space survived as long as they did when they had brand new games up and running in actually playable condition rather than the busted āproof of conceptā style emulators weāve seen in the past for then-current systems.
Itās still annoying, mostly because Nintendo also did this for another reason: they absolutely dislike piracy, with all their being. They did this not only because the Switch 2 seems around the corner and it seems to be based on the current Switch, but also because they know thereās a large scene for piracy that uses these emulators. Too bad Nintendo only attacks the surface heads, not the large root network underneath from which this grew, although I believe they planted that seed.
Iāve read they are also go after Youtubers showing their audience footage of them playing a Nintendo game and calling that piracy or copyright infringement.
I donāt know if they do that now, but there was a time you couldnāt use their music as BGM, no matter what, unless you joined a partnership with them, where they would take a cut of that money. Likeā¦ Nintendo operates like in 80s and 90s.
Theyāre specifically targeting people who are showing off emulation, not people who happen to be streaming/playing Nintendo games on their native hardware.
Itās something I follow reasonably closely - I am absolutely a retro gaming enthusiast and have a huge collection of devices and games on both original hardware and emulator systems, including both software and hardware emulation. Itās a big hobby, haha 
With that said, even as a person who makes use of the possibilities that emulation offers, I can also understand and respect that Nintendo have the right to protect their IP. From my perspective, I donāt have to like it, but Iām not going to get on my soapbox and start decrying them over it 
- these have always been the rules of the game in the 30+ years that this kind of thing has been possible, and we just have to continue to grow and adapt as we always have.
I think itās going a bit far not allowing people to show emulated Nintendo stuff on Youtube. If they dislike Emulation so much they should provide a way to keep playing games on devices that are deprecated themselves. Since they donāt they shouldnāt complain, I can see what they donāt like it done to current devices which the current Switch still is. But for games where you canāt buy the devices for anymore, they have no right to complain if they arenāt willing to provide the service for that themselves.
Itās a difficult needle to thread and thereās really no answer to it that satisfies everybody.
I feel that the thing to bear in mind is that the games (not the physical, held in your hands cartridges/discs, to be specific, but the actual content/data/whatever you want to define it as that makes up any given game), ultimately, are Nintendoās to do what they want with. If they donāt want to sell them anymore, thatās up to them. If they donāt want them to be made available to people, thatās entirely within their rights - itās their property.
They absolutely are leaving money on the table as a business by not selling the games anymore, but that doesnāt mean they should instead be free for anyone to take and do as they will with them - this may seem a very strange sentiment to be sharing on a board thatās built around a community thatās highly focused on the concept of FOSS, but consider this - thatās software freely given, not software thatās simply taken without paying for it
They canāt stop people from selling and trading their own physical copies (as much as I can imagine theyād like to, just like any other media producing organisation on the planet and like a significant proportion of PC software managed to achieve back in the day - cd keys anyone?) because thatās that individualās physical thing to do what they want with, but a dumped cart/disc changing hands in the manner of a ROM or ISO (and the changing hands part of this is the key, because many places already allow for you to make a copy of something you own regardless of what the platform holder says provided the copy is for you and you alone) is very clear-cut piracy by the measure of just about everyone on the planet bar a lucky few who live in jurisdictions where thereās no such thing. Whether you agree or disagree with piracy being morally acceptable, itās (in the vast majority of places) legally unacceptable.
This then circles back around to emulation - people showing off and promoting emulation products running these games are, intentionally or unintentionally, perceived to be promoting the idea that itās perfectly normal to do the same thing yourself and further propagate the cycle.
Again, my hands are absolutely not clean - Iām definitely not in a position to throw any stones from inside my glass house over here , but I think Iām taking a balanced view that these are the accepted parameters weāve always had to operate in.
Maybe Iām just incredibly old-school.
Sure itās a complicated situation and no easy solution but I did read somewhere that the copyright laws in Japan are stricter than anywhere else in the world. And that Nintendo seems to be trying to go after people anywhere in the world with the Japanese copyright laws as focus since it is a Japanese based company. That also doesnāt seem fair because there are different laws in different countries.