You make some good points, and I do not disagree with you about officers duking it out with perps. But when you say:
Why do policeman or statetroopers need to know how to box with gloves on? That kind of training is for sport and the ring not for the streets or law enforcement.
I disagree. Sport is just an aspect of training. The idea is to get the officers used to hitting and being hit with energy and resistance. This is a daily occurance for some officers on the street (one of my best friends and his wife are police officers).
In the same way that you would recommend BJJ for officer training (despite probably hearing "but you don't want officers rolling around in the broken glass", etc ), that is not the point to have them groundfighting just for the sake of sport. They are learning timing, energy and movement by boxing and BJJ, etc.
Certainly some better control should be excercised - and probably some better medical attention as well - but this seems like throwing the baby out with the bath water. Will they stop firearms training if someone gets hurt or dies on the range? Again, no disrespect to the fallen cadet.
"In case you ever wondered what it's like to be knocked out, it's like waking up from a nightmare only to discover it wasn't a dream." -Forrest Griffin