Have you ever served? I have plenty of reasons to believe otherwise. The enlistment oath is:
I, (NAME), do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; and that I will obey the orders of the President of the United States and the orders of the officers appointed over me, according to regulations and the Uniform Code of Military Justice. So help me God.The Second Amendment is part of the Constitution that every service member has sworn to defend.
As to the "obey the orders" part, notice the qualifier "according to regulations and the Uniform Code of Military Justice". The military is not obliged to follow illegal orders.
Our military is killing American citizens overseas in their undeclared pseudo-wars; may not be constitutional, but it stinks to high heaven. These people suddenly find consciences when it is within the US?