kbnrylaec: Fan fiction, fan film, fan music, fan art, dōjin, are very common human culture.
If you can not accept fangames, you should also reject all other kind of fanmade art form.
The SNES version of Doom was a fangame initially, and what id Software do?
They happily approved the fanmade SNES game, and make it canonical.
Nintendo could do whatever they want, to protect their (dead) IPs.
Their behavior is totally legal and reasonable, but many people like me still think they are stupid.
I don't accept fan fiction. All the Star Trek stuff people produce, Game of Thrones, etc. is taking another persons work and tarnishing it.
50 Shades being fan fiction of Twilight (I have never read either, but am familiar from those who have and know how the series started).
Ms. Pac-Man was originally a project by MIT students, then put out by Midway without approval from NAMCO, but eventually became the most successful fandom game ever.
If you're driving web hits and revenue off property that isn't yours and you have no license to use, you're trading off the back and work of others - excluding fair use (news stories, reviews, commentary, research, etc.).
We're not going to agree on the fan part, as to me there is a clear difference between fan work of painting a room or making a mural of Nintendo IP and wholesale ripping them off by making an entire game using their IP to distribute around the world.