Question

Why did Hitler segregate the Jew before world war two happened?

Answer 1

He did that to prevent any Jews from escaping when he sent them to the camps. There are large group of Jews in Germany and will create conflict during the war. Also, it will be harder to put them in concentration camps after the war since soldiers are going to war instead of in prison them

Answer 2

I believe he lost WWI and blamed it on the Jews, he used them as a scapegoat and grew to loathe them with a passion.
This hatred caused him to segregate them and make concentration camps to kill millions as well.

I could be wrong on the WWI, but I know he used them as a scapegoat. Correct me if I am wrong.
Hope I helped. :)