Are they serious, like showing images of Musk doing this is unlawful?
Potentially, which I guess might have been the entire point. The ZPS is no stranger to provoking law suites, and since Musk did this in the US this might be their attempt at baiting the German jurisdiction to take a stance on it.
That said the article you linked says the police talks about having an “Anfangsverdacht” (initial suspicion), which basically means “we have heard about it and will look into it”.
Can’t speak to historic usage, but today “am” (an dem) means “on” or “near”, and “im” (in dem) means “in”.
So the literal translation would be “lick me in the arse”.
Once saw a (German) documentary about this building. They have drop-off places on the ground floor where delivery drivers leave their goods in locked boxes. Payment and and locking/unlocking of the box is done digitally through phone.
P.S.: This one https://www.youtube.com/watch?v=PgVXPEORuA0
As the link in the post body explains you may direct your complaints to https://old.reddit.com/user/HEPS_08 of the r/stalker subreddit, although I’m sure they have heard about it in these past four years.