Those aren't claims, it's automatic Content ID. In this case YouTube has every right to prevent music from being uploaded and can prevent you from removing the Content ID claim, even when you have a license/it's in the public domain, because YT isn't abiding by or invoking the DMCA at all. It's like saying "guitar tryouts just don't play stairway to heaven" - you can forbid it even in the absence of AT&T sending a legal cease & desist your way.