Why is the danger sickening? Of course the equipment is dangerous -- it all exists so you can kill people and not die well beyond any natural level, and there's no such thing as a free lunch.
Sickening like working a construction job. When you're killing yourself in slow motion (the impact, the noise, the chemicals!), and there's no way out.
Most injuries involve an element of luck or skill, and the ego serves as a natural buffer.
Consistent, unavoidable, permanent, self-inflicted damage is different. It hurts in its own (sickening) way.
The special forces tale is heroism - being brave and tough in dangerous situations.
That the danger comes from your own equipment, used as intended, is just sickening.