I'm not sure if it is a shame. Try to imagine yourself as a deaf person who has been living in silence for many years, perhaps all of your life. Many people who can hear tell you how wonderful it is to hear, and you learn about this wonderful device that will help you to have this wonderful thing in your life called "hearing". You get the implant, they snap the magnet on your head, and all of a sudden your peaceful world of silence is shattered with sound. I can imagine how some people would rather have their peaceful world back in short order. Their can be many other reasons why a person would give up on it quickly and all of those reasons could be valid for them.
I have not read many stories about people's experiences with CIs. I am reminded though of one that my sister told me about a lady she use to know at church who received a CI when she was around 30 years old. Not too long after the device was activated, she got up one morning, put on her receiver, and turned it on. She exclaimed to her husband, "What is that horrible noise?" It was rain.
I love the sound of rain, but it was horrible to her. (Her CI was a Med-El also. I don't know if that means anything.)