Ah, the "abandonware" excuse. Ho could technically skate by, most software devs of ancient shit don't bother to sue unless they still make a decent profit off it, but it's still theft.
The ONLY way what Wu is doing is 100% legal is if he bought the ORIGINAL cartridge, ripped the ROM off with a cartridge dumper, applied a translation patch, then made his own ROM with a SNES flashcart, slapped a custom pseudo-official label on it, then played it on the original hardware.
Of course, he's likely bullshitting, since there ARE Mac SNES emulators.
Edit; It's even legal to emulate it if he bough the original rom, translated it, and then emulated it, but I doubt he did. Just buying the original rom is not enough if you emulate it, you need to rip THAT rom specifically and you can do what you want with that rom alone, playing it on an emulator with a rom ripped off the internet is still not entirely legal unless it's been released into the public domain.