The headline might be somewhat misleading if you do not read the article. It is not the federal state of Germany that is starting to switch to LibreOffice, but one of the member states of the federation: Schleswig-Holstein.
Shifting to LibreOffice is only one component of the the state's strategy towards a digitally sovereign IT workplace. You can read more about the other elements of this strategy here: https://www.schleswig-holstein.de/DE/landesregierung/themen/... (in German).
What is very interesting is the political background: Schleswig-Holstein is governed by a coalition of the Converservative party (CDU) and the Greens. In past decades it had been the Greens who where among the most driving forces for the adaption of open-source software and open standards in the public sphere, while the Conservativs primarily sided with big business. Now the latter seems to change gradually. Interesting times ...