Not really; The emulator doesn’t use any copyrighted code, but the ROM is copyrighted. That’s just basic IP law.

What is fucked up logic is Nintendo encrypting their ROMs, then providing decryption keys on the console. So the emulator itself is legal, but actually booting a ROM requires decrypting it, which requires keys from a legitimate console. Nintendo has argued that those keys are illegal to use in an emulator, even if the user rips them directly from the console that they own. So you have the keys. You own the console they’re stored on. But it’s illegal to use those keys anywhere except on the console they came on, because Nintendo said so.