> Which only protect a small area

We have these things called wheels. Or you could mount it on a drone.

> Meanwhile your guns shoot birds and once in a while - an occasional bystander

We are discussing protecting military bases or military assets.

> Some drones just drop grenades

That requires flying above the target. See counter-point 1.

Please put in the minimal effort needed to follow through at least a few steps of argument and counter-argument in your head. I assure you I am not putting in as little effort into my arguments as you did.