Same idea as Gen. Paul Van Riper's strategy in the Millennium Challenge war games ( https://en.wikipedia.org/wiki/Millennium_Challenge_2002 ). He spammed the enemy with cheap speedboats and motorcycles, forcing the organizers to rewrite the rules to make the game "fair."
I guess a cloud of drones can probably be shot down with some sort of EMP. It's unclear to me how to ensure the EMP is powerful enough to go through the shields of the drone without damaging the systems of the warship it protects.
Both of these articles are fascinating - underdogs with clearly superior strategies dominate, and rather than learning from that, the powers that be just change the rules to prove themselves right. How shortsighted