I disagree with you Ian. The rap anchor allows for descent with a single rope and cord tied loosely (not the knot) around the trunk of a tree does much less damage than people walking/standing around. Soil compaction, which leads to erosion, is a much greater threat to cliff top environments than sling anchors. Better to finish route and rap than traipse around on ledges and cliff tops.
Which might be fine IF it wasn't predicated on people only arriving at that location from below. Instead it creates a new descent point that folks topping out on other climbs will gravitate towards i.e. foot traffic, tree damage and the problems you point out at yet another point on the cliffs. I'm all for reducing rap traffic on people ascending.. it would be nice if that could be managed more effectively given the crush on popular routes on weekends. I just don't agree that slinging trees for convenience is the solution. Plus I don't think a single 60m won't get you down from the top. You end up at that dangerous rats nest with the rusty time bomb pins.