Of course it's not solely an attack on law abiding folks who own the game. But is is an attack on them nonetheless. Its also an attack on open source, software freedom, and digital preservation. Further, assuming there were legal threats involved, its an abuse of the legal system to harass open source developers working on perfectly legal software. Emulators are also direct competition to Nintendo's hardware, so you could see this as an anti-competitive move as well. There are lots of problems with this, and they're only mostly Nintendo's fault.
It's not unusual for law-abiding folks to be collateral damage for criminal activity.
One example I saw recently on here: locking up stuff in supermarkets. It sucks for real consumers because now they have to go out of their way to buy a razor. But it's intended to discourage theft.
The difference is that that is even worse, IMO, since the vast majority of people affected are real customers. For this switch emulator I'm not sure this is the case - I'd say the vast majority are people pirating.
I feel like the blame mostly lies on people who pirate games. It's a sort of tragedy of the commons. We could have a better world (Nintendo not caring if we play switch games we bought at 4k60 on a PC) but people who pirate games mucked it up.
It's also important to remember that emulators exist without ROMs.
All the code that's in an emulator isn't infringing on any Nintendo's IP -- it's re-implementing Nintendo's hardware interface.
That it can be used to make piracy easier is unfortunately, but isn't really the emulator developers' concern, given...
There are substantial, legal, non-infringing uses.
In most legal jurisdictions, thankfully you can't ban something useful just because it might be used to commit a crime.