His ideas of Aryan supremacy fed into his ego-drive for a 'superior race' as his legacy. It is our ego that strives to leave a legacy, and when this ego tramples on or disregards the legacy of others, it is egocentric.
When I was looking this up I discovered that Hitler did, apparently, have blue eyes.
> if the immortals actually made life shitter for everyone else, you can assume they would be French Revolution'd without too much overture.
The most proximate cause of the French Revolution was a tax on the aristocratic classes, and increased taxes in general, quite similar to the American Revolution: https://www.britannica.com/event/French-Revolution
Another cause was shared with the Russian Revolution: Gradually increasing rights for the hoi polloi that made them acutely aware of the unjustness of the constraints that still existed.
The aristocrats provided the wealth, and the hoi polloi provided the numbers. But in an immortality scenario the aristocrats are being given a privilege, not taxed against it. Or if this immortality is available to all, then the old immortals may outnumber the youth.
In the case of France, an emperor replaced a king. In the case of Russia, a dictator replaced a czar. In the US the previously existing legislatures continued ruling, but without oversight.