Crossing arms are meant to break away for just that reason, and they're not government property. They're owned and maintained by the railroad. The crossing, rails, lights, gantry, grade - those are all railroad maintained and owned items. Authorities will generally pave the grades, but the railroad has authority over it. Instead of a consumable device that probably wouldn't have netted him anything more than an angry letter from the railroad, he now has a destroyed truck and probably totalled trailer (with cargo damage,) potentially damaged locomotive, potentially damaged rails and crossing grade, the arm and it's connection points and possibly electrical systems for the arm, and probably will never drive a truck again. The train was in full emergency reverse brake, and the stoppage and strike probably means that the NTSB will at least have an investigator look at it. He ran the risk of derailing the train and all of it's cargo, which Is Not Good. You're right in that he may not have been able to logically think clearly about just backing the truck up, he was probably locked in flight mode with the train barreling down on him.