I think every western army does that. Or at least did, as you said. But it’s a moot point in this situation. If you’re ordered to guard a building in the middle of the night, you assume that it’s at worst just something inconsequential and stupid. “Oh now they want me to stand here for some reason? Sure, I guess.”

They weren’t gunning down civilians or anything like that. Shooting people floating in the water after their boat was blown up is a much clearer violation.