German here. It is indeed one user who missed pizza day today at work, posting many pizza memes in a short time.
The German community on Lemmy is rebuilding at the moment as their main server feddit.de was abandoned by its admin. Now the communities are slowly transitioning over to feddit.org. During that process, single users can be largely overrepresented until the communities found a balance.
I am not sure but I think you can disable certain languages somewhere in your user settings, so that German communities should not reach you anymor3.