Duh. As 911 states, this stuff rots livings forests, but somehow it doesn't have any effect on humans. It's kind of like saying rat poison works on rats, but is perfectly safe for people? In a war, it's easy to use an untried methods of killing the other guy, without full knowledge of the consequences. I'm reminded of the GIs , who were ordered to watch atomic blasts in the 50s, and who, then, came down with cancer.
And as to the VA, it depends on when you served, what laws were in effect at that time, what superseding laws changed all that, the VA's budget, the commitment of Congress, etc., etc. To figure out the "VA' system, you need three lawyers, 4 doctors, an accountant, two historians, 18 witnesses, some dice and a Ouija board.