An open letter is more for the edification of one's fellow than to communicate with a specific person or group. Any attempt to communicate with the antis mentioned by 45G is clearly futile. What 45G was saying to me is that he believes that it is ironic that the govt would train him to serve it and then not grant him the right to serve himself and/or his community. There is nothing incongruous about that at all. Their power does not come from the constitution but from their ability to coerce people to enforce their will by force of arms. The imminent Graboids have no intention of granting rights to anyone who is not serving them directly.
The 2nd amendment was to prohibit the federal govt from infringing on the people's natural right to self defense. The 2nd amendment does not grant any rights. The Constitution is not perfect but it is better than what we have now.
As for constructive criticism, may I suggest that 45G refrain from referring to himself as a trained killer and mock the Gun Graboids instead.