Is gelding an appropriate punishment for a horse who is constantly misbehaving?

I keep threatening to geld my horse if his behaviour doesn't improve. It's now to the point where if he does one more naughty thing he's being sent off to get gelded.Am I over-reacting or is gelding the appropriate action to take when your horse is naughty all the time?

Here's a list of bad things that Marely (my horse) has done:
- He ate my ham sandwich that I left in the box of my pickup while I was fixing the fence
- He ate my iPhone 4
- I let him borrow my computer and he looked up "mares in heat"
- I bought him brand new horse shoes and the first thing he did was walk through a bunch of mud and horse poop
- He NEVER cleans his stall when I ask him to
- He peed on me
- He peed on Chad
- He peed on himself
- Every time there's a full moon he stands outside neighing at it

You have replied to my questions with unnecessary answers to them. Why do you even get on here if you are not going to be serious? People go here to get REAL answer's to there important questions and your wasting peoples time. Please go on somewhere, you are not needed here. You obviously know NOTHING about horses.

I watched a documentary on food and they castrate male animals so the meat is more tender. If you castrate your horse, he will resent you because he will think you are raising him for meat.