Cases like this are frustrating. Spotify should NOT be able to stream any artist they want without paying them. But the judge said that's OK because the victims waited too long to complain. The judge also said it's totally OK that Spotify doesn't have a list of what is legal for them to stream, simply because the list is constantly changing. This isn't a paper list typed out by some secretary. This is a computer database that can be checked a thousand times a second.
There's also the fact that who was the actual copyright holder was questionable and changed hands during the whole thing, so nobody knew who they should be contracting with.