This is complicated. I think that the problems are much deeper than most people realise and I don't think that ordinary, front line police officers actually know what sometimes goes on. And of course, that includes retired police officers.
Personally, I've had a couple of bad experiences with aggressive, rude and pig ignorant police officers who seem to think that they know everything and that they can interpret, or invent, law to suit themselves. But, in my experience these people are very much the exception, most are the exact opposite. I strongly support 'ordinary' police officers.
But I do have experience of serious misconduct by very senior police officers. I can't go into details but I am actively fighting a police force right now. They have 'interpreted' events in a way that entirely suits them and which is totally contradicted by their own forensic crime scene evidence. Other, vital forensic evidence has not been disclosed. A Superintendent has produced a written statement that can easily be proved wrong in Court, but doing so will cost an unbelievable amount of money, and that money will be lost unless I can PROVE that this has been done for malicious reasons. And this person has the full support of someone far more senior.
What can be done in this situation? Well, the obvious thing to do is to make a formal complaint. But that complaint has to go to the police force that caused the problem in the first place, the IPCC won't investigate it themselves. The complaint is then 'investigated' internally, and the result is a foregone conclusion.
The next stage is to complain about the investigation, to the IPCC. But the IPCC can only investigate the process, not the result of that process, so unless they can find serious flaws in the actual process - and they won't - their hands are tied.
Local MP's won't help, why should they? As far as they are concerned, the proper process is to complain to the IPCC, and if that has got nowhere then it seems to them that due process has been followed and that the victim is just someone who doesn't accept that the police have acted properly. That leaves just the Courts, which is incredibly expensive. If the police win, they get an award of costs, but if they lose then they are protected against costs (unless, as I said earlier, malice can be proved) which is virtually impossible.
THIS is the problem - the cover ups, lies and skullduggery that is carried out at or near the top, and which is done in OUR name.
Obviously, I only know about this case, the case that this thread is about is very different and I don't know anymore than anyone else who has seen this video, but it seems to me that with that case, even if the police officer in the video has behaved badly, at least someone above him has dealt with it. But I can't help wondering what might have happened if that video hadn't been all over the internet...