Youtube blocks all videos they don't have the rights to. If an indie label refuses to give google the rights to show their videos, then youtube can't play those videos. That isn't youtube blocking indie labels, it's indie labels refusing to licence their music to youtube.
If read it four times, but the logic in this statement is bizarre.
Your first sentence clearly states "Youtube blocks all videos they don't have the rights to". That's YouTube doing the blocking. Period. Of course they can play those videos, copyright hasn't gotten that far out of hand yet.
Youtube is doing the actual act of implementing the block, but the only reason youtube blocks anything is because the content owner requested it to be blocked. They play/allow everything they have the rights to. Google is not telling the indie labels "fuck you, you can't have your music on youtube", the labels are revoking youtube's licence to broadcast their works because they don't like the way youtube is planning to broadcast it.