Diamond said:
I think it would be impossible to express any ideas at all on religion without giving his opponents ammo.
That's absurd. Even expressing an idea contrary to what someone believes doesn't hand them a counter-argument. I've disagreed with one particular southern Baptist I know on the continued relevance of religion in moden society, and I didn't hand him a ready-made hole in my argument.
Run with the notion that all Christians believe that Adam and Eve only had two male children who managed to populate the Earth with their offspring, and you're setting up the straw man of "something Christians believe" specifically to knock it down. A Christian who is familiar with Genesis will point to their "facts" to refute you.
Randi's done this before. His determined belief that martial artists breaking boards is a carney stunt is a straw man as well. Speaking from experience, board breaking is not a matter of mystic energy; the energy is very real and very physical. There's _technique_ yes, but that's it... no magic. Anyone who says so is a fraud, but JR can't/won't see the difference.