Judges make the law in this country due to our common law system. The law from 1885 may say that fencing off legally accessible land is illegal, but according to the land owner the supreme court said corner crossing is illegal so the fence in this situation would not count, because it wasn't blocking legal access. The question that matters here is whether corner crossing is allowed, the fence question follows.
It absolutely is not. Corner crossing was literally illegal right up until this decision came out. Using fences to enforce that was absolutely allowed since the public land was technically not accessible. This is far from the first case about corner crossing, hopefully it will be the last.