Not just the USA
“Someone had fired a shotgun straight up in the air into a 16-count fibre optic cable,”
A long time ago, on the other side of the world, in another life as a telco tech, we'd routinely run into problems traceable to water ingress on aerial cables caused by shotguns. Even if they don't sever the fibres/wires, damaging the jacket is often enough to cause long-term problems.
Dickheads are dickheads the world over. If road signs have shotgun damage then they're unlikely to be the only thing in the area that got targetted.