There are more implications to the ROE than chaining or unchaining our troops. Going all out sounds great until you find out how you have to go home because the host country that was going to let you stage an airbase didn't approve of your approach and denied you access to one of the only airfields within range of the conflict.
There are also moral implications that are well written about in Just War theory and other philisophical approaches used to justify the condoned murder of thousands.
Executing a prisoner under custody is indeed a war crime under articles 3 and 4 of the Geneva conventions. Posing for pictures demonstrates a lack of good order and discipline. Firing on a motorcylist who does not meet the criteria for a hostile PID is a disregard for ROE designed to control political and military narratives.
One of the reasons we avoid knee crippling power anymore is because as soon as you start slaughtering a civilization by the thousands, you start to turn the narrative of the conflict against you. This brings unwanted repercussions like economic sanctions, or drawing in additional adversaries. You can't fight the whole world.
You can hate it all you want, but war, and the military, are by nature, political instruments. If you ignore the political component you are going to lose.