Is there any good reason for content creators to refuse to sign? It sounds like they earn just as much money, so what's the issue? Sure, being forced to sign a contract is lame, but the new contract doesn't seem to harm them in any way.
Her biggest objection was that Google was purporting to tell her when she could or couldn't release a new song on various music services. It seems they've backed down on that. Google claims they were never asking for that, while Keating claims they quietly changed the terms.
She also objects to Google dictating a very narrow range of options for how she interacts with people who use her music. She doesn't like the "stick ads on all of it" option that Google is steering her toward, because that's not a strong enough enough response to people who are using her music commercially without licensing it, but also she would rather not stick ads on her fans.