Merkel may be twisting in confusion more than usual lately; but, for the sake of fairness, I’d argue that part of her problem arises from the dangers of having laws on the books that are tolerated because cultural norms typically prevent their unbridled use; but which are actually pretty toothy.
If abuse of the local lese majeste provisions were a common problem; they’d have either agreed that Preserving the Dignity of The Head of State is actually worth it; or people would get annoyed and the law would be fighting for its life. If, within the context of German political life, the law is considered mostly an anachronism; not something you’d touch if you wanted to be taken seriously; that makes it seem harmless until someone who absolutely doesn’t share your mores on the matter shows up and requests that the law be applied the way it says on the tin.
Hardly a uniquely German problem, or even unique to speech-related laws: it’s always a good idea to ensure that obsolete laws are appropriately neutralized and sent to processing facilities capable of safely handling them; not just left to ‘discretion’ and sorta-kinda repealed; but probably a bit more of an issue with European speech-related laws since there isn’t the (by no means automatic; but not dependent on the legislature) culling process provided by assorted retro laws getting a first amendment beatdown if anyone actually tries to use them.
In absence of that, even if your own political culture is commendably self-restrained and doesn’t even need judicial beating to keep it in line; you are still open to the first person who has both standing and no interest in what is ‘commonly accepted’.