It's a shoehorn because it is literally being forced into a plotline where it otherwise doesn't belong, much like, oh I dunno... having our characters suddenly high-five Shaquille O'Neal during the victory pose at the end of Brayflox's Longstop would be a shoehorn. Even if that's the
only place in the
entire game we'd ever see him (because we uh... we rescued him from a mud drake! Yeah, that works! The writers put it in, so it's canon!), would that hurt the core story of XIV? Not necessarily, but it sure would put some people off, wouldn't it? (You see, Shaq played a genie in the movie Kazaam, so we could just say that some kid 'wished' him into XIV, and because the developers made it happen, it's suddenly canon. Yes.)