Ah, I hadn't thought of that sort of slingshot! I was thinking more "primitive rock throwing."

There is also a cost aspect of it as well.

The long range drones that are being shot down are the "expensive products" of a military industrial complex.

The US solution to this problem is even more expensive.

For the cost the Ukraine's solution might as well be a rock: https://en.wikipedia.org/wiki/Sting_(drone)