One can understand, sort of, when a person steals something. It’s evil on a personal scale, a sin, and “all have sinned and are deprived of the glory of God.” (Rom 3:23) One can deal with it.
One can even understand, though less clearly, when a band of 40 thieves plunders a small village.
Even mercenaries are in it for the money. It’s distasteful, but no one is deceived about their “serving the country” or “securing our freedoms,” least of all they.
World War I, say, was not any of that. Neither was the nuclear bombing of Japan. They were destruction on the global scale for its own sake.