You don't think the Entente killed civlians, looted, or conscripted laborers from occupied territories? (Even if we ignore the broader context of how they treated their colonies!)

Also, while Germany was carrying out unrestricted submarine warfare, the Royal Navy was busy - literally starving - Germany, with its unrestricted naval blockade. Their justification was that soldiers eat bread - therefore, bread has a military purpose, and can be blockaded.