The only thing I've ever heard about it is that you'd have to wash all produce you bought and my exact response has always been "Are you people not washing your produce after purchase!?"

Edit: Also a lot of y'all seem to think we'd be throwing raw untreated human waste directly into the fields. We don't even do that with animal fertilizer. It's treated waste that removes a lot of the toxins that would cause us to get sick (again only if you're not washing your produce which you should always do regardless)