Why did the Nazi target individual groups?

documenting Nazi policies of systematically destroying national and ethnic groups, including the mass murder ... specific term, referring to violent crimes committed against groups with the intent to destroy the ... existence of the group. Human rights, as laid out in the US Bill of Rights or the 1948 United Nations ... of European Jews. He formed the word by combining geno-, from the Greek word for race

Because hitler didn't like Jews and only liked people with blonde hair and blue eyes because he felt the blonde hair blue eyes were way superior.