Actually, we are talking staff officers here, and their resignations would not be considered desertion. Nazi officers were convicted at Nurembourg for saying they had to follow certain orders. The judges said no, they should have resigned. Of course, the Third Reich would have considered such a resignation a shooting offense, on the spot, I would imagine.
American staff officers who don't care for an operation should resign, we don't want them around anyway.
All that said, the article is complete BS, so none of this matters, other than as something to discuss.
Now field officers is a different story, in that case you would be correct, it would be a court martial offense to attempt to resign in the field upon being given an order.
Of course, it wouldn't be desertion. But insubordination at the very least. I agree that we wouldn't want them around anyway. If they want to put conditions on their service, then demote and discharge. Or refuse their resignation, and send them back to officers school.