Google says that they claim to pay their artists but the artists differ. It might be stealing, but OTOH, you could say the same thing about Apple’s claims (which succeeded in Court) that Motorola was stealing their technology. I guess there are varying degrees and individuals have to decide what is appropriate for themselves.
Also, I’m not so sure why streaming should be stealing at all. I can play you my CDs; why should it matter that we have found a new way for me to play it to lots of people at the same time? And before you argue that if the law had conceived of this technology it would be illegal, the same is true of a million ways that corporations (such as the record companies) make money. The only difference is that they have the clout to actually make laws that protect themselves.