It means people can’t enjoy nature without wanting to change it. Their hubris drives them to leave some mark because the material world has taught them they’re important, and when they find themselves in raw nature they realize they’ve been sold a lie. The only way to cope with that feeling is to leave the mark of man on what was untouched, to shape nature into the unnatural, and stand back and say “I did this. I, I, I…” (It also means anyone with trail sense will kick it over. Cairns mark the trails out there and people following stacked rocks can get lost. People should have more respect.)
Well said, Red. I have a similar policy regarding “Fairy Houses”: if they were clearly built by children, using all-natural materials and are reasonably unobtrusive, I leave them alone. If otherwise, I destroy them and scatter all evidence of their existence. No need to leave evidence of human creativity everywhere we go.