"Free Palestine, F Israel" being treated as a threat is consistent with how all other Palestine/Israel speech is treated. E.g. in the UK if you said that in public you'd be considered a terrorist sympathiser (which is criminal). If you said it in Germany you'd be considered a Nazi (which is criminal). If you said it in the USA, they couldn't directly criminalise you based on speech but they'd find something else, like public nuisance or being a terrorist. So I'm not really surprised by this at all.
Antisemites use the terms “Zionists” as a dog whistle for Jews. I can show you threads on HN where it’s obvious from the context or where they’re used interchangeably.
This isn’t a new idea either. The Polish ethnically cleansed much of their last remaining Jews in 1968 with a campaign against “Zionism”.
The German government either does not understand that, or pretends not to understand that. Saying "F Israel" would be treated as a hate crime against Jews, which is treated even stronger than a regular hate crime due to history.
