soooo...
in ancient times, infants were sacrificed to gods.
in city-nations (sparta is one notable exaple because you've seen hollywood movies about it so it exists) kids that weren't entirely normal were either killed by the parents or simply thrown over the wall outside the city and left to die.
in Africa, the infant death rate among normal children is very high. abnormal children have a minimal rate of survival and will be the first to starve if it comes to that.
among other news, ISIS kills lots of people, including healthy kids. and nobody really cares. yet if they say they want to kill disabled kids, which they don't see anyway, everyone blows a gasket.
ISIS threatening to kill disabled kids is akin to the klingons declaring war on the smurfs. it sounds bad only if you have never heard of either.