Because
in a thread nominally about doctors, nurses, dentists and hospitals, there's an awful lot of I HAVE A WILLY and THIS GIRL TOTALLY WANTED TO DO THINGS WITH MY WILLY and not very much about doctors, nurses, dentists or hospitals.

Also, 95% of the time (or, on the internet, 99.9 recurring % of the time) when a man calls a woman a nympho he means either a) she enjoys sex, which women are not supposed to do; b) she enjoys sex but not with him and he's far too New Man (tr: Nice Guy) to call her a slag; or most commonly c) he is lying through his teeth.
(Shinigami, Mon 15 Mar 2010, 19:08, Reply)