There ARE veterans and SSI recipients who ARE mentally deficient and probably dangerous if given a gun. They should NOT be allowed to do so but that determination must be made by a judge in a court proceeding called for that particular case - NOT by a GS-9 clerk who just happens to be in charge of the computer that prints the signature of her boss. According to the Constitution, no one is to be deprived of life, liberty or property without a court order to that effect.
And are even more dangerous if you give them a few grenades.