I get the feeling that if Bayonetta 2 were on XBox 3 or PS4, the "I have to buy a new system?!" argument would not be quite so prevalent.
Most likely because the people who are complaining already had every intention of purchasing one of said systems, but didn't plan on dropping the money on a Wii U. And that's the crux of the matter, isn't it?
It seems the narrative that's being pushed here is that if you had no intention of buying a Wii U for whatever reason - the controller may not be to your taste, you may not be a big fan of Nintendo's first party stuff, or what have you - and you're reluctant to turn around and buy one anyway just because
one third party game you're interested in has been announced as an exclusive, you're "childish". You're not permitted to express frustration at the fact that had the game been announced for another platform, you wouldn't be looking at a choice between dropping hundreds of dollars on a system you're probably not going to get much use out of otherwise, or passing on a game you're really interested in.
I understand that Nintendo's adherents want to see them do well, and hope that third-party exclusives like this will help drive system purchases. But for that to happen, the library's going to have to achieve a certain critical mass, where people who weren't particularly interested before will look at the Wii U and say, "There's a bunch of stuff coming out for this system that I'm interested in and won't be able to play anywhere else. This is worth buying," whether in addition to one of the other consoles or (for single-console purchasers) in place of one.
Until that happens, though, you're going to see people getting annoyed about things like this, and I don't think that's unreasonable.
