There are several moving parts here.
First, there is the question of rank. The Police Chief obviously holds authority over a sargeant. As a commander, the chief has the right to address any personnel issue at the point of violation, which the sargeant appears to have knowingly violated. We do not see the jacket, but the subordinate seems to confirm he is wearing something non-regulation. The insignia on the back seems to be objectionable. I did not see any reference to it in the article(s). The chief performed the code correction away from the public and other officers, in a relatively private setting, so there should not have been so much opposition.
The officer protests that is in process of conducting a DUI arrest, which seems like a weak excuse for blowing off his commander, as there are obviously multiple officers working the arrest.
When the chief pursues the officer, likely due to his walking away from the disciplinary correction, the officer refuses to acknowledge the authority of the chief, which very much seems to send the wrong message to the public and to fellow officers. Authority IS the point of the police force. When an officer contradicts authority in a public manner, he's setting up a contradiction for his own legitimacy. It would be different if the chief had ordered him to do something illegal or unethical.
When the officer refused a command given to him by a superior, the chief tried to force him, which resulted in an over-the-top physical confrontation by the officer. He had the option of pulling away, of registering an objection to an illegitimate command, and invoking it before his fellow officers. Instead of either of those, the threw the chief onto the car, a clearly abusive physical response, not unlike the entitled abuse we sometimes see from angry officers out of control when arresting criminals.
However, the next comment, from the officer to a peer, is that "he's drunk again." That likely is the mitigating factor. Presumably the chief drove himself there, so his conduct may have been nullified by his violation of law in coming to the arrest. Further, he may be habitually harassing the officer, hence his coming to the site of the arrest. We don't know.
The officer was back in place after department review, and the chief on suspension at the time of the news story. That suggests a larger story than the altercation. It might be simply the strength of a police union or departmental politics.
What I see in the short clip shown is more damning to the officer who refused to obey a command from a superior and tried to legitimize it by making verbal excuses when there did not seem to be safety or urgency at stake. I would not want to be subject to stop or arrest by the violent officer. He escalated the situation instead of taking the proper action(s). That is the hallmark of police abuse where they kill citizens 'cuz reasons.
