Having never been one of us - the imperfect, the undesirable, the "defective", perhaps you can never know. I will tell you what I know.
I WANT TO LIVE.
Do not judge whether I want to live or die based on what YOU want me to do.
I'll guarantee you, this child's life is a damn site better than most of the posters' lives on this board. Why? Because SHE KNOWS SHE IS LOVED FOR WHO SHE IS. Who among you can say that? Who among you who calls for this child's death can say that you know that if you were afflicted as she is, that you would be loved as she is?
You say you would not want to live that way? It is because you do not know if you would be loved. You do not know that there are people in your life who would do anything for you, sacrifice for you, make your life beautiful in spite of hardship.
This child, and all of us like her, who have found love and joy in spite of our "imperfections" pity you. We know what we have, and we wish your lives were as beautiful if as hard, as ours. Our lives are beautiful because of love.
This child would not want to be you, nor would she envy you. She will someday have what she longs for - normalcy - and she will still be loved. You will someday be old, and feeble, and perhaps as repulsive as she - but do you know you are loved?
You are loved. You just don't know it yet...
As for your personal experiences, the zealot is always certain of his/her own righteousness.