Do you really think a person deserves a bullet in his chest for blocking a public way? It was a divided street and he even circled around to use only half of the entrance to what looked like a gas station.
You're right, the officer did say that he was not going to detain the protester in the beginning. When the protester decided to walk off on a cop who is trying to do his job to determine if there is a threat in the area, that's when things escalated to the point where the officer did legally detain him on reasonable suspicion.
The officer saying "my street" has absolutely no reference to him actually owning it. I call Houston "my city" but that makes me no more of an owner of it than either you or him.
Being armed is totally different from being black, white, or any other race. It was out of the ordinary enough to cause an alarm to send an officer to investigate. I saw a car going 10 mph down my street (the street that I live on with the rest of my community, not the one I physically own) multiple times a day, with people inside looking around. The police couldn't do a thing about it until someone (me) called in a suspicious looking vehicle. Once the officer was there in his patrol car, we never saw the car again.
I don't believe one bit that open carrying a rifle in Texas is against the law, or even a microscopic reason for it to be a "suspicious" activity to raise alarm. As far as I know, the protester committed no crime before the incident. Whether or not this is true, the officer was sent in to assess the situation to make sure that no crime was currently being committed and that it was safe to the public for the man to continue. And you're right, you aren't required to show identification to an officer, since Texas is not a "Stop and Show" state. But walking away from an officer who is sent in to to investigate is just one of the many reasons that I believe the protester was out to piss off a cop enough to film him and put it as a viral "Cop hates armed citizens" youtube video.
What the officer did right was his job: to Protect and Serve. He was sent in to investigate a call of a suspicious person and determine if the community would be safe. The officer detained him until he could prove his identity, which was fully legal, and released him when his superiors told him that there was nothing more they could do at that point. He was more respectful than he could have been, and way more than the protester was.
What did the protester do right? He instigated a situation with the the officer so that he could show a video about an officer trying to take his 2nd amendment rights from him. This is just another one of the reasons that we are fighting an uphill battle to get Texas as an open carry state.