I’ll defer to my father on this...
In 1967 he chose to ignore two potential deferrals (1 medical & 1 educational) to accept his country’s call to arms when he was drafted. When I asked him why he replied… “If I didn’t go, someone else would be forced to, and if they didn’t come home I’d be devastated.” So I asked if he agreed with the war and he responded… “No, but that’s irrelevant. I’m an American. My government said it needed to be done, so I did it.”
As a member of the military you lose the right to decide which battles you fight. That decision lays with the CinC, the DoD, and the Joint Chiefs, not the individual soldiers, sailors, airmen or marines.