Political changes don't happen all in a minute; both the voting age and the draft were Nixon projects, and they happened in a realistic time frame.
As for your claiming that I insult the military...I have not the words.
I find this (below) dismissive and insulting of soldiers (including Corporals and Sergeants that range in age from 18 to 21.
"But the fact is that while being 18 means you can hold a gun and shoot it where you are told, it does not follow that you have the capability to judge what should be shot at."