I’m also curious to know why Niantic has decided to remove trail marker spots in the Netherlands. According to the guidelines these are legitimate poi if they are “great places to be social, exercise, and explore” noting that “the trail is the interesting feature” and not the trail marker itself. This is particularly disheartening since these kinds of trail markers are often found in rural areas - areas that are in desperate need of more Wayfarer points. I walk and cycle in the countryside a lot and it’s sad to see the number of Poké Stops decrease every day.
Source: Trails & Markers - Criteria Clarification Collection - Niantic Wayfarer (nianticlabs.com)