I doubt these are words that a "banned". Probably more like words that trigger extra precaution in certain contexts. Medical terms like "testical" are perfectly reasonable words.
> goatse<p>oh no, not this again<p>For those who don't know: <a href="https://en.wikipedia.org/wiki/Goatse.cx" rel="nofollow">https://en.wikipedia.org/wiki/Goatse.cx</a>