It's just naivete. The man is a military Veteran, he believes in the system, maybe he's a Blue Lives Matter supporter. Does he know that highway robbery via cop occurs all the time? Does he know not to trust cops who get massive kickbacks? Does he know he's not obligated to answer their questions and submit to their searches without cause?

To me, this all says: naivete, a lack of learning. If the cops want to escalate it and infringe on his rights, he can then lawyer up and fight it.