This here is one of those internal contradictions of capitalism.

Contributing factors include:

Condensing people into atomized suburban areas thus taking up surrounding nature space from cities.

Car dominant infrastructure means no public transit to travel to outdoor recreation areas that exist outside the city, and typically outside of the suburban areas as well. This causes a high entry cost barrier to lots of people.

The ones that do exist are few and far between, leading to overuse and overcrowding. This is exacerbated by very little gov funding going to conservation efforts, and very little effort educating the public on outdoor conservation practices. Smokey the bear type PSA’s, outdoor groups like Scouts (though these have their own problems), etc

Social Media is a scourge upon humanity, driving people that aren’t there to enjoy nature but instead get internet points. This group does not maintain the trails and is in direct opposition with nature enjoyers, hence the sign gatekeeping that particular group.

This absolutely is gatekeeping, and it’s a direct effect of capitalism