“This article isn’t an indictment of plumbing drains but rather a commentary on the sloven nature of most people.”
Where in the article does it say that?
Any part of the plumbing system that can affect you like the article suggests, by definition is above the trap and therefore available to you for cleaning. There would be no point in the study if they meant the plumbing down stream of the trap. Everyone already knows not to play in the septic tank or in raw sewage. If your contact lens or open wound contacts plumbing after or below the trap you are taking your recreation in the wrong place.
...infections in humans, typically entering the body through wounds or trauma, via catheters and intravenous devices or by introduction of a biofilm to the eye. ...In one high-profile case, Fusarium was found to have caused a widely publicized 2005-06 outbreak of fungal keratitis -- infection of the cornea -- among contact-lens wearers.
Wash your counter tops, kitchen sink, lavatory sink, toilet and tub and you won't have these problems. These surfaces are dirtier than you would believe. That's why I said; “This article isn’t an indictment of plumbing drains but rather a commentary on the sloven nature of most people.”