"If the Samaritan is on the road bleeding, most atheists I know would help him."

But the question is, if it were a fanatic, Bible-thumping evangelical on the road bleeding, would the atheist help him? It's a little unlikely he's going to come upon a Samaritan on the road bleeding. On the other hand, he may come across a Hebrew in distress - as in the original story! But the point really is that it's a nominal enemy ...