You know german bad language?
Erm...much of them just are animal's names...donkey...pig...and so.
Some are "idiot" that are not only German.
And some are just funny, like "Sockenwärmer", "Sandsackprügler" or "Landstraßenpistenrowdy"
But such words are not really used and not commonly. Every one would have ideas of other funny "bad language words".
The really bad words are often rassistic or discriminating disabled people, imigrants or religious believers (for example [only one!]: Nigger. Nigger or Neger has been used for blacks commonly for hundreds of centuries, for example by the people in the last few centuries. And nowadays this expression is discriminating and rassistical (and, of course, forbidden), so one nowadays says "Schwarzer" (black human) or "Farbiger" (coloured one).)