I've heard people saying just the opposite. It couldn't run TotK before official release, and whoever made it run had to modify it independently (because it's an open source project)

Arguing that people wouldn't have downloaded it if not for the emulator, not only once again assigns blame to the wrong party ("if they didn't have motorcycles to get away they might not have stolen it"), but it overlooks that there are modded Switches that can run pirated copies too.

Pirating stuff before it's even out for sale is pretty sketchy, but Yuzu is not the one doing it. It simply lets people play copies they already have, including those they may have dumped themselves. Nintendo is encroaching on customer ownership rights by trying to argue even doing that is infringing.

edit: Maybe my analogy is lacking because one might argue that they rely on the tool to make use of the illicitly acquired thing, which is not necessarily true for a motorcycle. But if we say instead "the bluray player is to blame that people shoplifted" or "the media player is to blame that people downloaded pirated movies", then I believe it should be even more clear that they are accusing the wrong party.

The only way for Nintendo's reasoning to work is if they try to argue that not even someone who dumps their own roms and extracts their own keys from their own console ought to have the right to do it. Which would be disastrous for customer rights and preservation. Nintendo cannot be allowed to get away with that.