IF people are shooting specifically to take down power lines, fiber cables, or insulators, they are vandals and what they are doing is criminal. If you want gun nuts to stop getting all riled up every time something like this happens, we need to quit identifying the entire gun culture as complicit in the crime every time some asshat runs off and does something stupid with a gun.
We wouldn't accept that kind of generalization imposed on us, and we shouldn't do it ourselves.
I have known many hunters in my life, and grew up in MI hunting deer and small game yearly. I never used a rifle for vandalism or in any other irresponsible fashion. I never engaged in "boredom killings" which I think is disgusting. Most people I met through hunting were the same, but there were a few assholes, and to be clear about it, the assholes were assholes irrespective of them being hunters or gun owners, they were assholes in all other contexts as well.