The video that was released and shown of the arrest that night is only a brief fraction of the entire event that happened. Rather than jump to a conclusion and assumption of what is right and wrong, we should all allow the investigation into the entire incident to take place.
Lt. Hudson immediately reported and documented the arrest and subsequent use of force and now an internal investigation is in progress. When the investigation is concluded and all the facts are known, then and only then should anyone form an opinion.
The small problem with this view is that it subtly offers a defense not available to Hudson. Multiple witnesses — and the video — say there was a period at the beginning of the video with no contact between Hudson and the man he punched repeatedly in the face, Chris Erwin. Erwin was even able to text a girlfriend that he was outside the restaurant. Nothing — NOTHING — that happened before the beating can justify a punchout. That can be justified — and police are taught other means to subdue suspects — only by imminent threat to the officer and evidence that Erwin was resisting despite officer force. Did that threat exist after Hudson's first punch? The second? The third? The fourth? These are indeed questions for the internal investigation.
Police have been known to get riled at jerks and "tune them up" as Sipowicz would say. They've been known to sweep complaints under the rug. Videos make that harder to do. I merely urge skepticism about the evolving police fallback — believe unimaginable horrors you can't see, but don't believe your lying eyes.
Neither police nor anyone else who throws a punch is offered a legal defense by earlier "fighting words," a spilled glass of wine, general boorishness, a refusal to leave a restaurant (clearly Erwin left) or anything else invented by police defenders who've commented here so far. The trigger of the beating, its repetitious nature and whether repetition was necessary to subdue Erwin are the only issues.