Well, the lines on a map are an artificial construct that contribute to the political unreset within the region even today. The British and French ignored a long history to divide up the region to suit their interests.
The only meaningful boundaries are military frontiers, like those between Iran and Iraq. What I would like to know is why the victors chopped up the Kurdish nation and gave their territory to the Arabs and to the Turks and to the Persians. But then these were really supposed to be colonies or protectorates not national states.