Rileys Mountain Trail, anyone know whats going on?

On the weekend I rode out to the Nepean lookouts and planned to ride Rileys Mountain Trail to the Nepean Narrows Lookdown. What I didnt expect to find was a recently machine graded single track (i was under the impression it was illegally done as i couldnt understand the purpose of the track. It was in an awful location as far as water management goes and didnt really lead anywhere. There was 3 existing prints in the soil, one mountain bike, one horse and the machine tread itself. I walked the trail as every couple of metres a spider web was across the track. I followed the track and soon found myself on existing old firetrail/double track. This ended up at a gate on the back of a private property. I back tracked a little to a fork I had passed this then forked off again. I decided to explore onward. The only existing prints in the soil i could see now was from a horse. I followed this track which passed an old looking gate/fence. I also passed the back of more property fences and ended up on a difficult single track and to my amazment there was still horse tracks.
Ive seen horses on the firetrail several times, but has someone purposefully made a singletrack for their horse? I was confused. The difficult single track ended back on the firetrail and avoided the big hill climbs upto Rileys Mountain lookout. I continued onto the Nepean Narrows lookdown trail and found the trail here had also been recently graded with the same machine width. Now this made me more confused. If it was graded by NPWS then what is the purpose of the first trail I found. Its not wide enough for vehicle access to the back of the property and servered no real purpose I could think of except for catering to the horse riders. On the return trip I rode(cough walked) back upto Rileys Mountain Lookout and here too had also been graded by the same machine. I was so confused now, what was the purposed of the Machine cut single track that lead to the back of a private property?

Just to note, this trail is not worth it for Mountain biking. Stick to the firetrail.