Your argument is correct in every way.
But I would argue that the
consverse isn't true either. You can't say that if they use it, it won't work.
The SEALs, for instance, need a wide range of training in order to counter likely threats. Remember, of all the units, the SEALs and other specops are more likely to go h2h. The nature of their missions sometimes require the stealth of bare-handed assassinations. If they bungle this, then they have to deal with the problem swiftly and get out!
BTW, I wouldn't call what Paul Vunak teaches "sweet" or "innocent." His stuff is quite capable of killing on the instant
As for the Marines, I've read in a recent combat magazine (note, "combat" not martial arts), that the Marines have developed a new system based on the old WWII Applegate techniques mixed with some grappling and kickboxing. From what I saw (still shots) it looked pretty effective. They train in body armor too.
The Rangers train a clipped version of BJJ, what they claim are the 13 "core" techniques taught to them by the Machados. These are said to be the easiest techniques to employ and most deadly. In fairness, they never claimed they were teaching h2h; they say they are training the Rangers to think under physical pressure, which I think is one great plus for any martial arts training, as well as BJJ.
I'd like to know what those 13 techniques are.
So not all military martial arts are useless. You have to look at it from the point of view of a combatant. What are you training for? It isn't always to kill or maim. They have specific objectives, you know.
Anyway, that's my two cents