Call them privies, latrines, outhouses, etc. These toilets are usually built a safe distance from the water source, in a soil that promotes breakdown.
Human waste is often a carrier of disease.
The best way to avoid contamination is to remove the possibility of contact with feces. On the AT in Maine, because of such high use, outhouses are the best LNT method. This reduces the risk of exposure. If left to cat holes, people may run out of places to poop, or make poor choices contaminating water sources and right around the site, making them unpleasant. A way to bury waste that avoids water contamination and prevents animals and other humans finding it.