"Not to be indelicate, but since this isn't actually a camp, what facilities are these "campers" using?"
Not to be indelicate, but they're probably just crapping wherever they wish. It's not as if they actually understand how one gets cholera, after all...
You've just uncovered one of the reasons that the "final" Woodstock ended so violently.
On the first day, attendees had deliberately broken water systems so that they could play at being "mud men". Toilet facilities suffered and attendees resorted to crapping in bags and tossing them in the trash or wherever. After a few hours/days in the hot sun, thousands and thousands of bags will STINK. Something you don't grasp from the safety of watching in your living room.
Hippies act first and complain later.