Is this statement true?

[Almighty Colin]

Two interesting subjects in one thread (or is it one?).

There are definitely rules in war. Different cultures have different rules however. People sure get upset when other cultures don't play by their rules. Witness the US labelling of some of the Iraqi actions as irregular
or "criminal activity". That activity was called for by Saddam however. Many in the Arab world consider such attacks to brave and noble while many of us in the west consider the same acts to be cowardly and weak. No side is correct. It's just culture.

Not all rules of war make it more difficult to achieve victory, however. A vastly outnumbered side should run away to regroup more often. Throughout history the culture of war has often been to show bravery and honor and stand and fight. In the pre-gunpowder age such a rule lead to getting the battle over quicker. The greek hoplites had such rules of honor.

Even the idea of not targetting civilians is a rule that is sometimes in existence and sometimes not. Why should civilians be off limits? That's arbitrary.

At the beginning of World War II, civilian areas were not bombed. By the end of World War II it was so accepted that nuclear weapons were dropped on civilian areas. After the war the rule "don't use nuclear weapons" became a rule and don't sell nuclear weapons became one too.