You have to understand how US law works. If you are not an injured party, you can't sue the government for it. In other words, Google cannot sue the government for the injury government is causing to you. What they can do, however, is claim an 'injury' on First Amendment grounds, reasoning that their free speech is limited when they cannot disclose that John Doe is being surveilled (and thus John Doe is being injured). They do that with the hope that with transparency John Doe will have the information necessary to sue the government.