Why period destroyers do not need 6-inch guns

Are these destroyers armed with 6-inch guns?

No. They use 4-inch guns, which are more appropriate for destroyers of the period, although some French and German designs experimented with weapons around 5.9 inches.

The destroyers carry 4-inch guns rather than the 6-inch weapons the viewer inferred from the battle. For a destroyer of this period, a 6-inch mounting would be unnecessarily large for the ship's role and dimensions. French and German designers did experiment with unusually heavy destroyer armament, particularly weapons around 5.9 inches. The answer separates the appearance of the game battle from the actual design choice and places that choice against national exceptions.