Yeah, that's something he discussed here as well.
Some posts of him (among others):
http://forums.nesdev.com/viewtopic.php? ... 39#p159139
http://forums.nesdev.com/viewtopic.php? ... 25#p159575
Another excuse not to release anything (as in: "I was working on a game, but won't show it because the NA guys are dicks").
Regarding his Twitter post:
It's one of the few times where I can kind of understand him. NintendoAge users had the habit of creating reproductions that bordered on counterfeit products, having "F-1 Race" and "Miracle of Almana" carts (or "Ninja Gaiden" hacks with Batman etc.) in boxes that looked like genuine black box and Konami titles, including copyrights, the Nintendo Seal of Quality and all that stuff.
Although, in practice, the splash screen to discourage reproductions is pretty pointless if you never create any game to begin with.