Germany's 'freedom of speech' is just qualitatively different and much less meaningful. It's illegal to burn the German flag, use a diminutive to address a police officer (du vs sie). More troubling it's illegal to insult a foreign leader (and the government must determine whether criticism is 'abusive', which would constitute a crime)
https://en.wikipedia.org/wiki/B%C3%B6hmermann_affair
Chanting 'from the river to the sea' is illegal. Publishing statistics that suggest that refugees commit crimes at a higher rate. Calling a politician a 'criminal'. And of course the nazi stuff you mention. In general, 'human dignity' is considered more important that free speech.
I agree, the detention is insane, unnecessary, arbitrary, and a complete abuse.
edit: As to your other points - I would argue that stuff like the Böhmermann affair is a good example that free speech more or less works in most parts of Europe. Yes, there were - very old - laws about insulting royalty and heads of state. However, a state-financed comedian was able to push on those issues enough for those paragraphs to be changed/struck (as far as i remember, at least) - and he's still state-financed, still has his head and his freedom and still happily insults important people.
edit2: It's not really correct to state that the phrase "from the river to the sea" is forbidden, specifically. There are no legal means to ban specific phrases on a whim in Germany. There are, however, blanket bans on using phrases/slogans of organisations that are unconstitutional such as terrorist groups. The argument has been made that "from the river to the sea" is a Hamas-slogan but as far as I've kept up with the discussion, there are different legal oppinions on that and there's no final court decision yet.