Wow, I'm surprised at how many people find FPS games to be boring. I'm just the opposite. I think multiplayer in Halo, Call of Duty, etc. blows away the experiences found in games like Mario Kart. BUT, that's only according to my own tastes. I've noticed that Nintendo fans in general aren't too keen on shooter titles, perhaps because Nintendo really doesn't delve much into the genre. The lack of HD support doesn't do much to help that, nor does the Wii's controller design. Pointing and shooting with the remote really doesn't do much to help your aim IMO.
When you then consider how (presumably) popular Nintendo is Japan, that company is likely dominating how and what the Japanese think in regards to gaming. And if Nintendo generally shies away from FPS games thereby rendering the genre as a sort of Microsoft/Sony specialty, it's quite likely that the Japanese feel alienated from the genre in general. And if you don't feel connected to a type of game, you aren't going to want to play it. You'll find some way in which to critique it and dislike it even if your involvement with the genre is minimal.