“Which is harder to believe, that one set of God-made parents led to the human population, or a string of happy accidents made us (as the Athiests maintain)?”
Evolution does not equal atheism.
Your dichotomy, here, ignores the theists that accept evolutionary theory and/or hold Genesis to be a metaphor at best.
“But, where Atheists get themselves really twisted up is when they maintain that one can be an evolutionist and yet believe in moral behavior and non-violence (as many of them claim to).”
Or course we can believe in moral behavior. We’ve had morals longer than we’ve had the Christain or Jewish faiths. It’s how we evolved, as social animals that don’t kill members of our own community. Couldn’t have a city without that.
“When in fact, to be consistent with Darwinian theory one must do away with the genetically infirm,”
No, not even slightly. Darwin’s theory does not require that we trim our gene pool. That’s what the tigers are for.
“or at least not interfere with their elimination by natural means”
That would also preclude medicines, glasses, hearing aids, crutches, canes, casts…
But, again, we’re social animals, we protect out weak, sick, and halt.
“for the "good" of the species and its progression (or so the theory says).”
You have no idea what the theory says.
“ Even Darwin himself recognized that his theory would lead to some form of eugenics, eventually.”
Darwin never promoted eugenics, although unscrupulous people have tried to use his work to justify it. You’re either lying or you fell for someone else’s lies.
“Atheism is a very brutish religion”
And, again, you’re conflating the science with the TOTAL LACK OF RELIGIOUS THOUGHT and calling them the same thing.