/r/50501 Mirror

That's fine but why that grass specifically? If I'm understanding the picture right it's not convenient to walk on it. It's not like between two points you would go to. People aren't staying in this spot for very long either- they're walking up the street.

The left side of the photo is the street and sidewalk. People are marching "up" as the photo is oriented. If you came upon this scene from "down", the grass would be on your right. But if you for some reason left the sidewalk and went onto the grass, you would quickly be blocked by the wall that's in the center of this photo. People aren't avoiding the grass because of rules. They're not on the grass because there's no reason to do so.

This isn't a park. This is a little grassy section in front of the library. Go look at Google Street view or similar for w41st and 5th Ave.