The legal system is the perfect place for working out nuanced issues like this.

If I were a lawyer and making this lawsuit I would argue that "publicly available" does not mean "public domain", and that without acquiring usage rights for the data then you don't have the right to use the data.

If the courts rule against a decision like this then that would mean that any website that hosts any materials that can be accessed without an account must then provide that material to any person who accesses it free of charge which is a gigantic consequence to this nuanced issue.