Changing the brain is scary. That is our identity. Changing the body is way preferrable. We're used to our bodies being mutable. We're hardwired to know our bodies will change. Even if it's just in the style of dress, we are used to changing our outward appearance when we feel it's right, and with science, money, and determination we can change the flesh itself... But change the mind? Then you don't have the person you started out with before. GID is a part of all of us, has affected us our entire lives. Notice the word "identity" in it. Change that, and what you had before ceases to exist forever.