No, they weren't. It's true that the Europeans had better technologies in most cases, but they weren't necessarily more culturally, genetically advanced.
They mistreated the people they encountered because they were superior in terms of weapons and soldiers.
Because of the Europeans military power which were superior than those of africans
The nativist belief that northern Europeans were superior to southern and eastern Europeans
the Europeans felt they were superior to the africans
Hernan Cortes and Francisco Pizarro conquered the native people they encountered through a combination of military superiority, strategic alliances with rival indigenous groups, exploiting internal divisions among the natives, and spreading diseases that devastated the local populations. They also utilized advanced weaponry, tactics, and superior leadership to achieve their conquests.
Europeans had superior weapons, better transportation networks, and they had better communication networks.
The Nazis felt their race was superior to everyone elses
Writting system
Columbus wrote in his diary that the people he met would make good slaves. Right off he considered himself superior to the Native Americans he encountered. He saw them as heathen and the Europeans after him felt the same way. It was an attitude that came with the invaders.
The scientific revolution change the way Europeans looked at the world. Europeans thought they were superior to the rest of the world.
By weight of numbers, persistance in moving ever westwards, and by superior weaponry.
That the Aryan race (fair haired North Europeans) were superior to all other races.