Some homebrew games are ports of some legit original games, some are even open source ports like Hex-a-hop, which has been ported to the 3DS.
Companies like Nintendo just can’t stand the idea of their systems being unlocked due to the new ability to pirate their games. It doesn’t even matter if you have pirated, to them, they’l fight to push laws against modding consoles as well.
Bad on their part.
At least Sega and Sony mostly dropped their fearmongering/correlation fallacies ship after the Bleem situation, but companies like Nintendo and Irdeto insist on being setbacks to the market. And with devices more and more closing down on what the user can do, despite being glorified computers, a friend of mine would even say that “console modding is an act of self-defense”. Furthermore, if piracy is as rampant as such companies insist on saying, I wonder how much wouldn’t be a “problem of service”, as GabeN once said, and/or if perhaps they’re using correlation to justify limiting what people can do.