my take on this,
okay, from what I can gather by the video and the article there wasn't 20 cops that all showed up at first. I could see two officers that were obviously injured, one a policewoman who looked like she had bashed her face or nose somehow plus it appears she might have blood on her arms but maybe that is stain from the deck. The officers involved in the struggle to keep the man from entering his home called in that they were slightly injured and need assistance. Of course you are going to get every available officer on the scene when a call goes out like that.
The officers were called to the home on to investigate a report that the man was illegally discharging a weapon in his yard. It would seem that they have reasonable suspicion enough to request the man to identify himself. Are they supposed to let him ignore that and retreat into his home? I just can't see that happening and would even say its stupid to do so. If I were an officer and I was having difficulty fighting with and gaining control of a suspect who was trying to retreat into his home and I was injured, I would hope plenty of backup would arrive ASAP.
The woman in the house is probably pretty scared and upset at all of this as she has no idea as to why police showed up at her home and are now assaulting her husband on the front porch. The man wouldn't identify himself. Its not up to the suspected law breaker to be the one to decide if he's fairly or unfairly being accused of a crime. If the police have reasonable suspicion that a crime has been committed, its wise for this man to identify himself when its demanded of him.