Wether such "non-lethal" weapons at large should be included in the game is something that can be debated for a long time. However, everyone can agree that the game engine wasn't designed for that kind of engagement.
Now that's not the type of obstacle that will prevent some from trying!
I don't know if weapons with zero HEK screw up something in the game, I have been testing some and it went alright as far as I can tell. At any rate, the fact that non-killing weapons (or at least intended to be so) made casualties can be apprehended by assuming, as I think is the principle in the game, that a casualty can be as well some guy with his guts torn out by a mortar shell or someone temporarily knocked down and left behind by his team or playing dead.