Churchill had a way with words. But war was never much of a “gentleman’s game”. Armies on the march ravaged the countryside. And woe to some civilian who objected to his chickens being stolen.
After a successful battle a medieval commander might yell “cry havoc”, meaning his soldiers were now free to plunder, rape, and pillage.
Not very gentlemanly.
I’ll speculate that WW I would have been the first war in history where more combatant were killed than civilians, if it weren’t for the Turks going after the Armenians.