Well sorry to break it to you, there’s no international law making disinformation campaigns illegal. It was a bad order to be sure, but not an illegal order.
Soldiers are responsible when following an illegal order. When it’s a bad order, then it’s the person giving the order that’s responsible.
It’s just how military works. They have to follow the law, but not your personal morality. I mean what’s the morality around killing a person because they’re wearing a different uniform? Do you think that’s fine while a disinformation campaigns are crossing the line?