One more try
The difference was the humanitarian crisis that was occuring at the time of the invasion. Had Saddam decided to push all the Kurds in Iraq into Turkey and repopulate Kurdistan with Iraqi Arabs AND had actually sent in his army to begin the process then the two situation would have been analagous. We both know that wasn't the case. While Saddam was certainly bumping off a few political opponents, there was no immediate wide scale humanitarian crisis occuring that prompted an American military attack.