Yeah, linking disease with behavior has lead us down a pretty path. Of course, a Talmudic justification for circumcising a boy baby was to purify him from the carnal act that created him and that is stretching, you should pardon the term, credibility beyond the breaking point.
This same "leprosy" attacked houses! Historians are still not able to say what this was other than some creeping crud. If it did not go away after the place was vacated, the house had to be torn down and the stones and beams hauled out of town (1-800-GOT JUNK?). Seems like something could have been found to kill it, but maybe the Kohanim had lock on dealing with it and forbade any research by the laity. That would be typical also. I wonder if they cleaned things with hot water back then? Somewhere along the line, all of those rules for kashering stuff with boiling water were invented. I can't inmagine a baleboosta (an excellent and praiseworthy homemaker), even in ancient times, being satisfied with less than immaculate cleanliness.
"Have you tried a little boiling water on that moldy spot on your wall?"
"Do you think it would help?"
"Well, like chicken soup, it couldn't hurt."