Those who would kill the weak are themselves the ones that should not have children. However, I believe that the trend is towards merciless killing so as to 'improve society', as sick and 'defective' people are 'not what I planned for!'
I have a co-worker who divorced her diabetic husband once he began to lose his sight. She wailed, 'this was not a life that I wanted for myself.' She said that she had planned out her future with her husband, and blindness ruined those plans.
I do think her husband is better off without this cold-hearted 'person'. I still work with her and she still acts as though I am friendly with her, although I've given the cold shoulder to her from that moment on.