It also has something to do with the so called "Hackerparagraph" [1] under which whitehat hacking is basically impossible in Germany. Even writing a program that could potentially be used for hacking is a crime. If you followed the law word for word the authors of e.g. curl could be charged under this law.
1: https://de.wikipedia.org/wiki/Vorbereiten_des_Aussp%C3%A4hen... [de]