Is the parent actually being highly incorrect? Anti-semitism was highly popular at those times (e.g. Poland, Russian Empire, US). Nazi party were also popular

Is the parent actually being highly incorrect? Anti-semitism was highly popular at those times (e.g. Poland, Russian Empire, US). Nazi party were also popular in Britain (at that time) and other countries. Why would Weimar Republic specifically outlaw their nazi propaganda? Am I missing something, or is that specific paragraph related to only a short period of time?