He is a law enforcer officer by trade and duty. He took an oath. He isn't a Lawmaker. He cant back away from one side of his duties and expect not to be sanctioned.
He sure can if it's an unlawful order. And that is what he is talking about. That governors and the like are giving orders that are unconstitutional.
No different than the military. The very first words you say as you are joining are "I,
__, do solemnly swear that I will support and defend the Constitution of the United States against all enemies, foreign
and domestic..." And from day 1 are told that it is our DUTY to disobey an unlawful order.
If he is in fact fired for taking a stand, I hope he sues the ever-livin' shit out of them. I would imagine he would have a hell of a case for being fired unjustly and only as reprisal for standing up for what's right.