This post makes no sense. Your both cases are an example where was too much "free speech" (preeches) and too few ( govermental fight against Stürmer)
I guess the analysis about Nazis in the Weimarer Republik are far more complex than a matter of free speech. It tells a lot that I never heard historians seriously discussing it in this context.
The preaching was free but the challenges were not due to blasphemy laws, thus more free speech would allow challenges, which we know reduces the problem of bad speech.
> It tells a lot that I never heard historians seriously discussing it in this context.
If you got the first part wrong then the second is only telling in the other direction.
Firstly, that Germany's descent into fascism and anti-semitism were both helped by the lack of free speech. Blasphemy laws prevented the anti-semitism preached from the pulpits to be challenged, and hate speech laws actually helped the Nazis publicise their movement[1].
> Rather than deterring the Nazis and countering anti-Semitism, the many court cases served as effective public-relations machinery, affording Streicher the kind of attention he would never have found in a climate of a free and open debate. In the years from 1923 to 1933, Der Stürmer [Streicher's newspaper] was either confiscated or editors taken to court on no fewer than thirty-six occasions. The more charges Streicher faced, the greater became the admiration of his supporters. The courts became an important platform for Streicher's campaign against the Jews.
As to norms, they can be self-enforced because free speech allows such a choice, otherwise it would be the case that those norms were imposed or not even available. Most likely, they'd be someone else's norms.
[1] https://www.newyorker.com/news/news-desk/copenhagen-speech-v... Interview with Fleming Rose about his book.