Legend of Zelda: Skyward Sword [SPOILERS]

The boss was made to attack Link either way, I thought, considering what its guarding.

Fi's description of the thing said something about Ghirahim making it stronger than it was before, or something along those lines.

 Spoiler

As for Link being a criminal, I'm thinking the temple sees all people who enter as criminals trying to take something of great importance. That, or it was just a Buddhist shout out to some folk.