Hyrule at Hogwarts

When Link tries out a dimension-altering spell with the help of all our favorite (and least-favorite!) characters, the magic goes awry and they wind up in the middle of who-knows-where! Why are they there? Why is there so much magic in this place? Why is that castle called Hogwarts, of all things! And most of all... Why did we have to bring along GANON!