WEBF
Simple, it didn't happen!
As a Barrister I can assure you that you are spouting rubbish of the highest order.
Show me ONE instance of an infantryman being charged with using excessive force in a firefight with the Taleban.
If you really think that most criminal behaviour goes unpunished you try thumping someone in public view or on CCTV, I think you'll find you are in for a bit of a surprise!
I and a good number of my colleagues are rather closer to this than you are and I can assure you that our courts and our prisons are full of folk who thought they could get away with violent behaviour in public!