I find this statement deeply ignorant of history. I am no defender of imperialism in general, however, Hitler started his conquest with the idea of a systematic genocide of anyone not of the master race. He started with Jews and polish and had plans to mass murder Slavs, and eventually all the mixed races of the world.

Britain’s empires (there were more then one) were usually accidental and commercial in nature. They were not founded with the goal of deliberate mass genocide and replacement by a pure race. They tended to be extraordinarily under staffed for their purpose.