I can only assume YT bends over backward to cater to the copyright claimees so that the major labels keep uploading their copyrighted content to official channels.

Basically, at some point this conversation happened:

Label: We don't want to upload our music to YouTube because we're afraid of piracy.

YouTube: We promise that won't be a problem. We'll work with you to ensure you'll be happy with the state of things on YouTube.

The current system was born of that and nobody gives a hoot about the small/medium players who get screwed over by the insanity.