I agree with you. I can see the usefulness of a system like that prior to the Internet becoming so commonplace and especially during the Cold War, but not so much anymore.
However, testing/demonstrating/making a point with it isn't a huge deal. Its nothing new, the system has been in place since 1994 (1963 if you count the EBS) and I've never heard a single thing about anybody disagreeing or challenging its legality. The test will last for something like 3 min, its not like they're shutting broadcasts down for a day or even an hour.