There was a bunch of institutes for the "Erhaltung der deutschen Sprache" which were all founded under the umbrella of a quasi-propaganda organization that officially was just a society/club. [1]
They created their own "purified" dictionary with a "clean language" that was trying to find replacements for foreign words, and strengthen the nationalistic awareness with all its perks.
It was so ridiculous and opinionated that they tried to even enforce the use of "Nagelindiewandschlageisen" instead of using the Swedish word hammer.
They burned all their stuff in the war, but it's somewhat folklore that they were heavily involved with Goebbels and his propaganda in WW2.
They got away with that during the Nuremberg trials so technically this is an accusation from my side.
Culturally I think this is the opposite of what cultures should embrace. Languages will always evolve, and you cannot prevent that.
As a side-note: Those were so puristic people that they even pissed off Adolf Hitler at some point, because they criticised him for using foreign words in his speeches.
[1] https://de.m.wikipedia.org/wiki/Allgemeiner_Deutscher_Sprach...