Bear in mind that “free speech” just means you can’t be arrested for what you say.
When someone’s talk is being boycotted or - in this case - refused entry to a region, their free speech rights aren’t being infringed.
That said, I (and the French, it seems) agree with your sentiment, this is totally an appalling move by Germany.
My understanding of the joke is less about tables, more about pontification; I.e. “it is so because we say it is”.