While I quite agree that the farmer deserves compassion too, he made a conscious choice to let an animal starve to death. There were other choices he could have made that would have been far better and cost him nothing more than a little effort.
Like you, Simon was not given a choice. Just as you would not have chosen the streets at 15, nor would Simon have chosen his circumstances. Had the animal simply been turned loose ( animal version of the streets) he, like you, would have survived on his own. He could have found food and water. The movement would have worn his hooves. By penning him up and forgetting him the farmer condemned the animal to a painful death.
Should we hate the farmer? I could not. Should we hate the choice he made? Hell yeah. He could have called almost any animal rescue and let them re-home Simon. He could have given him to the 4H program who would have found him a home. He could have simply opened the gate and let the animal fend for himself.
We all need to remember a simple phrase that Tim understands better than most.
There but for the grace of God go I.