Can you blame them?
First off, the "implied" powers of the president by way of the oath of office end where the common soldier's oath takes over....
Mainly, we swear on oath to protect and defend the constitution from all enemies, foreign and domestic. The constitution says congress has to declare war, which means a soldier going to war WITHOUT a constitutional declaration of war amounts to something NOT INCLUDED in the armed forces oath.
People claim the president has the power to due things NOT explicitly defined in the constitution (such as these semi-wars) due to implied powers from his oath, however, soldiers take a different oath, and we don't swear loyalty to a president, on the contrary, if he is an enemy of the constitution, we swear loyalty against him.