I'm not sure that's as good an argument as you think it is. For example, if a government somewhere decided that disabled children were a drain on society and s

I'm not sure that's as good an argument as you think it is. For example, if a government somewhere decided that disabled children were a drain on society and should be killed at birth, it would be valid for a pro-lifer to oppose this killing while also not volunteering to personally raise all the disabled children in the society (or even one such child).