It's simple. Apple wants to launch with a credible claim of "all iTunes music" in their service. So they really really want you to agree, and probably make bloc

It's simple. Apple wants to launch with a credible claim of "all iTunes music" in their service. So they really really want you to agree, and probably make block deals with labels (who generally control streaming rights). A band like Brian Jonestown Massacre might control all or most of their streaming rights. The band is only important to Apple if they are helping Apple's marketing for Apple Music. It's heavy handed, but it's typical Apple: unless you are a huge partner, you have to sign up for the whole enchilada, no piecemealy crap. Hanging back a few months to ride the future success of Apple Music's marketing plan without being a part of the marketing effort? That doesn't really seem fair either. Apple has no time for hesitant minor partners. You're either in, or you're out. Unfortunate comparisons to George Bush and Heidi Klum are unfortunate.