For the same reason, the German language has very complex honorifics [0].
Some Germans take real offense if you don't address them with the proper honorific or forget to list one of their, oh so important, honorific titles on some text communication.
Because of this, there exists quite a lively market to sell honorific titles, specifically aimed at German-speaking users [1], in that regard there still exists a very real "class distinction" in Germany.
Stuff like that always makes me wonder how much influence population density has on the evolution of such strict social dynamics.
[0] https://de.wikipedia.org/wiki/H%C3%B6flichkeitsform#Die_H%C3...
However, I also found (particularly in written contexts) that the Germans were really big on formality. If you don't use their proper titles, they'll get very upset. If the paperwork doesn't have an official stamp on it, it's meaningless waste paper. If it does have an official stamp on it, then it's holy and undisputed, no matter what nonsense is written on it. I'm surprised that there isn't a flourishing fake official stamp black market because of the importance people place on those things.
I find that all the fluff in German written documents revolves around formality, rather than fake politeness. I always got the feeling that all those extra, meaningless words and phrases were more about doing it the proper, formal way (no matter how meaningless that was), whereas in the United States, the people are much more informal, but use a lot of fluff words to convey fake friendliness.
German academic writing is ridiculous. There's so much formality and academic vocabulary involved that they'll write long, complex sentences with fancy vocabulary to convey a simple concept. It's about as formal as you can possibly imagine, so it's wordiness and complexity has to compensate.