Adolf Hitler looked like a Jew.
If he'd worn a full mustache, he would have looked like he owned a Pizza Parlor.
So, he trimmed it down to distract those who took notice of the appearance of his fairly long nose.
He also had the sloping forehead common among Jews, as well as the characteristic sad sack eyes. Without the mustache acting as a distraction from the length of his nose, Hitler may have been seen as a Jew .... and the World would now be a much different place.