For other readers, the most closely relevant version of that article in English: https://en.wikipedia.org/wiki/Strafgesetzbuch_section_86a

(Clicking the "English" article from OP's link brings you to a version without that subsection)

It's grey area as of 2018. Technically will be decided on a case by case basis rather than just claiming that video games as a whole target the young and are therefore banned as a class from using Nazi iconography.

Wolfenstein 3D, specifically, hasn't been banned since 2019: https://www.schnittberichte.com/news.php?ID=15165