Why an unarmed Pearl Harbor overflight still means crisis

What if Japanese aircraft flew over Pearl Harbor all day without carrying or dropping weapons?

The United States would still intercept them because a mass unauthorized overflight violates national territory and amounts to either coercive gunboat diplomacy or the opening of a war.

Removing weapons would not make the operation benign. American aircraft would attempt to stop a foreign force flying over US territory without permission. At best, the display becomes a form of coercive gunboat diplomacy that humiliates the defender by exposing weak air defences. At worst, it is treated as an act of war and triggers the conflict the attackers claim to be avoiding.