It is not a pleasant thing to write about those days. Every sane human being may have his side of story to tell or his reasons for love or hatred towards anybody. I wrote this answer from the information available about Nazis and Jewish people.
As far as I know, After the world war 1, Germany not only lost the war but ended with paying huge amount of money to its allies. And German government had to print money to stabilise economy. But all these efforts lead to Hyperinflation. And due to this situation, poverty was everywhere. Germans were in miserable conditions.
We can’t even imagine the sufferings faced by German citizens during post World War 1. It was like a hell. Unemployment, poverty, crime, illness, death were seen every where. People had to borrow money from rich people to buy food and shelters for their family. Apparently those rich people were Jews only, as they inherited huge money after the fall of Roman Empire.
Jews were in the influential positions in banking sector. So Hitler and other Nazis blamed rich Jews people for every bad thing happened in Germany.
Another thing that went against Jews was the communism conceived in USSR by a Jewish Karl Marx. The Germans thought that the USSR will take over Germany like Poland and it was due to Karl Marx only. So Germany turned out to follow Antisemitism and hatred were spread among Germans against Jews.
So to protect their country people from the hands of rich Jews people, Nazi’s literally did genocide.
Hatred will never bring peace and prosper to any country. We hope that the world will never see those things in the future.
image source -allthatsinteresting.com