My guess is the leftover pasta and assorted food items mentioned in dedmiston's post were more likely from the previous user of the site scraping and cleaning their dishes into the firepit/ring their last night at the site so no campfire to burn up the waste, then washing them whether outside by whatever means or in their camper of some sort.
And if there is so much germ and disease in that grey water, and let's not be a jerk, responsibly dumped, then what would that say about the dishware we just washed with that same water? Whether the sink or shower, it's essentially soap and water.
Oh, on my two-month cross-country trip last Spring/Summer, the first campground we pulled into near St. Augustine, Fl, made the reservation on the road, I asked If I could pay an extra night's rate to be able to wash my motorhome and toad. Lady behind the counter says "I wondered why your rig is so dirty, I see you are from NY, No you don't have to pay extra, just wash it during the evening!" Washed our vehicles at least five more times on the trip at the campgrounds with permission!