Darwinian evolution operates by survival of the fittest and elimination of the weak, therefore, for the good of the species, the weak and disabled should not be allowed to breed.
On atheism, are there any transcendant laws that are being broken by this attitude? Can atheism ground any objective morals that would condemn such behaviour? Is there anything in the above statement which is inconsistent with an atheistic worldview in which we got here by Darwinian evolution? If there is, I don't know what it is. I'm not saying that atheists believe that's how they should live (because atheists are still made in the image of God with the work of God's law on their hearts, and thus they know better), but I'm saying that if they did live that way (as some have) it would be completely consistent with their beliefs.
Appealing to logic when engaging with Richard Dawkins seems to be a futile exercise when we remember that this is the man who said,
"The universe we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil and no good, nothing but blind, pitiless indifference. As that unhappy poet A.E. Housman put it: ‘For Nature, heartless, witless Nature Will neither care nor know.’ DNA neither cares nor knows. DNA just is. And we dance to its music."He speaks about evil in the world, yet says there is none. If there is no evil why should I be concerned about my behaviour or anyone else's? He says that DNA neither cares nor knows, and we dance to its music, yet he thinks we should care! If DNA doesn't care and that's what I'm made from and dance to, then why should, and how could, I care?
When we see such logical contradictions coming out of Dawkins own mouth, I'm not surprised he can't see the logical step from atheism to acts of violence - logic doesn't seem to be his strong point.
There is design, purpose, evil and good, and we know it. We are not robots programmed to dance to DNA, but morally responsible creatures, able to reason, reflect and choose. Atheism can't account for it - Christianity can. God is not indifferent. He is not indifferent to our sins, but takes them seriously (Hebrews 10 v 31; 12 v 29), and He is not indifferent to us, He loves, He cares, and He has shown it (John 3 v 16; Romans 5 v 8).