Short Answer 
The Nazis promoted a ideology of racial purity that sought to exterminate groups like Jews and Roma, whom they falsely categorized as inferior races. This culminated in widespread persecution and genocide, driven by distorted beliefs in racial superiority and the necessity of eliminating perceived threats to the German race.
Step 1: Understanding Nazi Ideology
The Nazis believed in a concept of racial purity that involved the extermination of groups they deemed inferior, such as Jews and Roma. Their ideology posited that these groups posed a threat to the German race, leading to the radical belief that eliminating them would enhance the lives of the German people. This belief was rooted in a distorted interpretation of survival of the fittest, suggesting that superior races had a duty to dominate and eradicate those perceived as lesser.
Step 2: The Definition of Jews as a “Race”
Nazis referred to Jews as a “race,” categorizing them based on a set of inaccurate stereotypes and biologically determined traits rather than their religious beliefs. They disregarded the Jewish religion and created a narrative that presented Jews as a monolithic group engaged in a struggle for survival at the expense of others. This stereotype contributed to their dehumanization, which was essential for justifying persecution and violence against them.
Step 3: Consequences of Nazi Racial Theories
The Nazi racial theories had dire consequences, leading to widespread persecution, incarceration, and ultimately the genocide of millions. Jews were designated as the primary enemy, which galvanized public support for oppressive policies and systemic violence. The Nazis aimed to create a dominant German race, believing this was a natural and necessary order, leading to one of the darkest chapters in human history.