Apparently, it works like this;
Games with Adult Only Tag are automatically hidden from german users, the tags are decided by the developer.
Pretttyyyy sure Fear & Hunger does not fit the Adult Only descriptor. Sex isn't in the forefront, and frankly there's worse sexual content in other games like GTA or Witcher.
I could of course also be wrong, but i'd love to have it on my steamlist. Heck, I'd even buy it again lol.
Would also make it easier to gift it to people.