This is absolutely true. However based upon the current (SR4A) rules, a single grenade could not kill any of the soldiers. The worst it could do is knock them out, assuming no one had a Body of 5 or higher. If that's the case, then they don't even drop unconscious. This is a terrible error on the devs part. Not grevious, but really not well thought out.
As for Narcojet? It does 10 boxes of stun, which is sufficient to knock out anyone with a Willpower of 4 or less. Should people with strong wills have a chance to go unconscious? Absolutely, and while the rules don't state that bonus hits boost damage of the toxin, they could be used that way to represent getting the toxin into an important blood vessel which would carry it straight to the brain (in the case of Narcojet). An extra box or two could represent bruising and some nosebleeds or some other biological effect.
One of the things that has always been really attractive about the SR game mechanics is that anyone can die from anything. Even if your character is a maxed out troll cyberzombie with crazy amounts of armor and whatever else one can think of, it is possible, just not likely, that grandma with AGI 1 and EDG 1 will one shot you with her hold-out pistol. This result is highly unlikely, but it exists within the realm of possibility based upon the rules. It means that the players can't just blunder through with certainty (hey, that sword only does 1D8+2 damage, I can take it!), they have to be aware that their characters may die in any combat. This encourages clever thinking and problem solving, and I heartily agree with it.
Now, back to the atuofire grenades, please. I'm really curious to see what others think (regarding modelling it).