No, that's not right. She can still publish her music on youtube either way. This is about signing up to the "monetisation" option where she can take some of the money from any third party video that ContentID says includes her content. She's currently using that service, and continuing to use it apparently requires signing up to the new agreement.

I'm not completely clear on this part, but I think she can still get ad revenue from videos that she uploads herself. The article is definitely talking about third party video uploads.