Totally Off-Topic

The silly controversy about "The Star-Spangled Banner" made me realize something. The original version seems to be in 3/4, not 4/4. So is England's "God Save the Queen." These tunes could be waltzes! What's up with that? Wouldn't you think national anthems would be marches? I remember how striking it was to hear Sondheim turn the presidential march "Hail to the Chief" into a lilting carny waltz for the opening of Assassins. Strange to think how close these hallowed national anthems already are to that form.
This sheet music has the signature as 6/4.