Just an opinion here, take it and filter it against your own experiences and knowledge.
Had to watch it to comment further. Here's what I saw despite the lousy camera handling, the dog never showed any signs that I saw that would indicate aggressive behavior, lowering of the head and ears tucking back (always happens when a dog growls defensively), rapid switching of attention from target to target (there were three from the dogs perspective), I didn't even see any telltale jerking that would indicate barking up to the point the choke stick was used.
What I did see, People who have no business being around animals. I've had to deal with the results of idiots like this who think only of dominating an animal with force, brings to mind dealing with horses and cattle that small minded morons tried to whip or drag by the neck into trailers. I also saw an incompetent female animal control officer who tried to do a job she didn't have the upper body strength for.
Looking forward to hearing more of the background and circumstance though.