Geoff,
To a certain extent, you are right. As soldiers, if we are resorting to h2h combat, the proverbial crap has hit the fan and something has gone seriously wrong. But also, as soldiers, ignoring the possibility that you may have to choke the enemy to death is dangerous. I take this view for a number of reasons:
1) As soldiers, our job is focused aggression. If we are focused, but not aggressive, we lose and die. If we are aggressive, but not focused, we lose and are dangerous to each other. I find this fundamentally identical to your various forms of real world fighting (ie grappling).
2) As soldiers, we have to prepare for every possibility and examining previous conflicts will show that at times, soldiers had to resort to using their bayonets, helmets, and whatever else came in handy. As I‘m sure you know, street fighting rarely follows a script. Neither does war.
3) As soldiers, we have to be desensitized to killing. It is not in our nature to kill other humans (some may disagree). Which is why militaries have spent millions of dollars learning how they can get their soldiers past the psychology burden of killing. Shooting square targets from 100m out won‘t do this. Getting two troops on a mat fighting it out, short of killing each other, in my opinion is very effective in teaching soldiers that war is not pretty. You may have to end up killing a guy face to face.
4) It‘s great for physical conditioning. Ask the Brits about milling.
With regards to your point that practicing h2h fighting could be dangerous, well our job, by it‘s nature, is hazardous to our health. I can think of dozens of situations in training where I can potentially injure myself (and at times, I have). If I were always concerned with injuring my knee, breaking an arm, or getting cut up, I may as well quit right now. Obviously, a certain level of restraint must be instilled so that we aren‘t just injuring each other.
Again, I‘m not saying the military should drop everything and focus on h2h combat. But it should have it‘s place in training, especially the combat arms.