How can you punish that you ask Saphroina?
Simple, you wrap a rope around his neck and throw him off a Gallows.
If you get one consiencious objector who "gets away" with it, what happens when the fighting gets tough and the soldier just wants to go home?
"Oh screw you General, I'm outta here."
You may not believe it, but Draftees even when they HATE that they have been drafted, fight every bit as well as a Volunteer who loves to fight.
But if you start letting people leave a fight any time they wish, then you have a collapse, which is unacceptable and causes "routes" which is when
the enemy, still in formations simply rounds up and slaughters a falling apart opponent.
It is those formations and organizations that win wars, do you think they just go "oh well I'll go over here, but not over there".
No it's, "I ain't going anywhere" but yet they do, and because they did, we won.
Reminds me of that "Blithe" kid on Band of Brothers (Great series).
The guy had an acute blindness that would trigger off and on, but no one knew about it, and he was very timid, hiding when the fighting was going
But good ol' Capt. Winters forced him to start shooting, and he shot a German Paratrooper, and took his little flower.
After that he was leading the pack, eventually took a bullet to the neck and died in '48 to complications from that wound.
But the point is, if he could just "consienciously object" any time he wanted to.
He'd have never fired a shot, ran off, and never helped to win the war in any way.
That's why this marine must be Court Martialed, which you know what that means