It wasn't the cop's fault New Jersey gun laws are anti-Constitutional.
The Fourth Nuremberg Principle ought to fully apply here.
Every public servant in this country, including that cop, takes an oath to uphold and defend the Constitution; and bears this duty above all else. There is no excuse whatsoever for any cop to not know that every free citizen has a right to keep and bear arms, and that as a public servant, he is forbidden by the Constitution from interfering with the exercise of this right.
“I was just following orders.” is not a valid excuse. Neither is that he was enforcing a lesser law, that he had to know violated the higher law.