Skimming over the article, it's a lot about what the copyright office said and very little about what courts said. But the opinion of the copyright office doesn't have any legal force. Regulations passed by the copyright office would be binding, but their opinions are just opinions. We will have to wait until relevant court cases reach a conclusion. And so far running litigation isn't even about that question, it's about infringing the rights of works that are in the training data