Is there no problem dumping grey water on the ground in campgrounds? My grey water doesn't have food particles or grease. It's only hand soap, or dishwashing soap.
Tent campers aren't showering and sending fecal matter into the Petri tank. They are washing dishware and affecting the next family tenting. These sites are on areas where trailers and rv normally can't.
Letting 40 gallons flow either through the stinky Petri slinky or right from the Petri valve is illegal in many states forget about local campground rules and regs. Fines and jail time are more effective.