Because the the entity was a ghetto and they housed Jews.
Warsaw - it was also the largest ghetto.
The Jewish ghetto police secured the deportation of Jewish people to the concentration camps. They were also not permitted to carry weapons.
Warsaw, it was the largest Jewish ghetto of all.
Jewish police
To segregate the Jews.
Everyone was Jewish! It was a strictly 'all Jewish' place.
the ghetto - or Jewish quarter was generally set up (where possible) in a non-Jewish part of town, so that they would not have access to their religious buildings.
The first attempt to set up a ghetto had been made by the SS in November 1939. In mid-November 1940 the Jewish ghetto in Warsaw was sealed off by a high wall. The Nazis did not use the term ghetto, but referred to the area as Jüdischer Wohnbezirk meaning Jewish Quarter.
It is an ironic scene. when the people first came to the Ghetto some of them belived it was a good thing, they were only Jewish people there. The Jewish people thought it is sate there, when actually there was no future in the Ghetto, only death.
30,000
Schindlers List
Segregated Jewish areas in Polish cities were called Ghettos. Hope this helps :)