Low-impact travel is taught as a set of principles rather than a set of rules, and the reason becomes obvious when the same principle is applied in two different environments.
Durable surfaces mean different things
In forest country, established trails and existing campsites concentrate impact where it has already occurred, which is the right approach where vegetation recovers reasonably fast.
In the desert, biological soil crust takes decades to reform after a footstep, so travel is directed to rock, sand washes and established routes instead.
Alpine tundra sits between the two, recovering slowly at short growing seasons, which is why walking on rock rather than plants is emphasized above treeline.
Waste disposal varies with soil and water
A cathole buried in forest soil is broken down by an active microbial community within a reasonable period, which makes burial an appropriate method.
Desert soil is dry and biologically slow, and high alpine ground is frozen much of the year, so material buried there persists far longer.
This is why certain river corridors and alpine areas require packing waste out entirely, using supplied systems rather than a shovel.
Fire rules follow fuel availability
Where deadwood is abundant and regrowth is quick, a small fire in an established ring consumes a renewable resource without much consequence.
Above treeline and in the desert, downed wood is scarce, accumulates over long periods and provides habitat, so burning it removes something that will not return quickly.
Fire restrictions also respond to conditions, and a stove is the reliable choice in any season when ignition risk is elevated.
Water sources set camp placement
Standard practice is to camp well back from lakes and streams to protect banks and to leave the water accessible to wildlife.
In arid country a single spring may be the only water for a wide area, and camping near it can keep animals away from the resource entirely.
The distance guidance is therefore a floor rather than a target where water is rare.
Why the principles are taught as questions
Memorized rules fail in a landscape they were not written for, and a visitor applying forest habits in the desert can cause damage while following instructions correctly.
Asking what this particular ground can absorb, and how long recovery takes here, produces the right answer in places the rules never anticipated.
Local land managers publish area-specific guidance for exactly this reason, and it is more reliable than any general list.