The problem is not who did the actual destruction of them but the laws of that state or city that required it. They would not demolish new cars or boats that are confiscated and should not demolish guns. These, if in safe condition should be sold at auction and that money go to the city budget to help relieve the tax burden on the citizens.
I do not blame the company that did the demolition I blame the people of that state for electing officials that pass such laws. In a democracy you get the government you deserve.