It's illegal, so no matter how many times you keep re-uploading it to GitHub it will eventually be taken down again and again. The more you defy Nintendo's DMCA takedown requests, the more likely Nintendo will notice and possibly try to track you down and sue you in person.
I understand that you want to show off your legal work (https://github.com/taisel/IodineGBA), but the only way to show it off is to require users to provide their own ROMs.
More proof that this is the same poster: https://github.com/playnintendo/gba/commit/e429bacd4d5fef715...
He forgot to change "jsemu" to "playnintendo" before re-uploading his repository to GitHub.