If you REALLY believe what you just wrote, I truly feel sorry for you. Also, this is hardly a shower thought; but is definitely a misguided statement based on your wild imagination.
The only factual part of your diatribe against US veterans, is the precept for war being a lie (allegedly also, since some claim they saw WMDs).
Vets have PTSD from many causes including getting blown to pieces from IED's, seeing their friends get killed or blown up, actual back and forth combat, indiscriminate mortar fire, death, destruction, even as simple as being in the theater.
So, stop this "they must have done horrific unspeakable shit so they have PTSD and can't talk about it.". There's probably a few dudes on the special teams that may fit your idea of mission secrecy, but you'll never know or hear about those missions anyway.