If you really want to discuss technicalities:

The institute was targeted by Nazis as early as 1920.

From about the early 1920s onward, Hirschfeld became a target of the far-right in Germany, including the Nazi Party. He was physically attacked during multiple incidents, including an incident in Munich on 4 October 1920 in which he was badly injured… By 1929, frequent targeting by Nazis made it difficult for Hirschfeld to continue with his appearances in public.