I've seen this many times but never in this country. France, Italy, Germany and, Spain I used to travel all over Europe to watch my team for a decade (before family) and policing in every Country is so heavy handed and still is. I have seen people battoned to the head, and I too have received blows just for being English and being in the crowd. When there is a crowd they will wield their buttons at anyone, including women and young teenagers!
If you were to assault a police officer in these countries I wouldn't like to imagine at how they'd treat you. You just don't do it. They get heavy handed to intimidate and stop anything happening before anything actually has! Our policing at football is polite and in stark contrast to nearly every other European Country I've been to and witnessed.
In this case, I have no sympathy for the guys if what they've alleged to have done is true(ie, assault female officers).
And although I don't agree with the female assault crime committed I do think the officer has over-stepped the mark. Particularly, the knee to the head after the kick. That was a head-gone moment. In this moment he was not acting as a professional.
I do however, believe that people should take into account at how hard it is to police and manage these situations. They were required to use physical force to gain control and, it is true that split second decisions need to be made. The officer in this particular scenario made the wrong decision.
If I was to assault not one but 3 female officers in an airport I don't think I could have any arguments as to the level of force I might receive in retaliation to that! I'm sure in some Countries I wouldn't live to tell the tale!