The national parks service philosophy is very preservationist. They advise people to follow guidelines that are literally called “leave no trace”. Their mission statement uses the word preserve in the first sentence. Hell, part of the reason why Big Bend national park never became an international park (among many others) was because the parks service disagreed with the laxer, conservationist approach that Mexican authorities favored.
>The point is recreation. This is why they are full of artificial modifications like roads, trails, and sometimes attractions with shops and bathrooms.
Those modifications are done carefully to have as little impact on the environment and a lot of types of recreation are completed banned in national parks, hunting being the obvious one. The use of vehicles (including bicycles) is completely banned in federally designated wilderness.
What steps did whoever installed this take to make sure that this thing isn’t going to leech metals into an ephemeral watering hole used by wildlife?