Once upon a time, I read a book on parasitology. In the the introduction, the author mentioned a copepod that settles on the eyes of a particular kind of fish, eventually leaving that fish blind. He mentioned that naive grad students would often assume that this was bad for the fish, lowered its fitness – but of course a sophisticate like himself understood that parasites always evolved to become harmless to the host, so in fact that induced blindness didn’t decrease the fish’s fitness at all.
I could explain how a better evolutionary analysis can indeed explain nonzero virulence, but that is not the real question. The real question is, what should we do with pinheads like this? There are whole fields in which the average professor is that loony. Come the Revolution, what should be done?