What is so secret about the stupid bakers hats that they have to keep it a secret? I think it goes back to polygamy, and those "hotel" rooms they had in the basement of the Nauvoo temple.
Because its supposed to mimic an eternal kind of penalty--the same kind as the way animal sacrifices in the old tabernacle of the old testament were done. Guns are a new invention. You could hardly argue that God's law is eternal if it involves shotting someone and guns did not exist in ancient times. Disemboweling has eternal law of God written all over it.
But disemboweling involves blades. Blades are a form of technology. That means at one time, God's children did not have them. Shouldn't they bash you over the head with a club instead?