My thought as to why that isn't good is because the game you play to get to the International (often online and in smaller venues) is a different game than the one you would play in the finals. As a viewer, I think they should be playing a higher stakes version of the game I can play, not one with different rules because of the crowd. Either way, I don't care so much, but I fall on the side of the sound proofing being good.

The competition is about playing the game they came there to compete on, not a different metagame. If you find that fun, that's okay but your tournament is in another castle

A baseball analogy would be if sign-stealing were allowed.