@Shadows, I quoted you only in so far as what you said was representative of a widely-held point of view. However...
Although some definitions cite parasitism as a form of symbiosis, I would say they are wrong. Symbiosis should be defined exclusively as being mutually beneficial (otherwise another word needs to be defined for this which would be a bit crazy).
That said, if Webmaster World refuses to give benefit to sites that, one way or another, it references, then I guess Webmaster World is the parasite!
Good businesses deal with each other in ways that are mutually beneficial - right now, Webmaster World doesn't seem to have grasped this properly. In the fight against spam (which is laudable) the site is being damaged - think "baby" and "bathwater".