Using Panzers as a metaphor for those who think we think we "ought to lend a hand" is rather appropriate. The Nazis were all for giving evolution a shove in the back. When we start talking about building the New Man, we might remember that we've seen those tanks before and they made a bloody mess.
We might also remember that we've got our own history in the US of trying to create a master race. We were less insistent about it than Hitler, but still managed to break quite a few eggs without getting anywhere near an omelette. Harry Brunius recounts the story in his new book, Better for All the World: The Secret History of Forced Sterilization and America's Quest for Racial Purity Sally Satel reviewed it in in yesterday's New York Times.
I appreciate that Derbyshire isn't suggesting that we fire up the eugenics movement. (At least I hope not.) Still, my guess is that he regards those who pretty much reject out of hand the notion that we embark on a program of human improvement as obscurantist and anti-scientific. But if science is, in part, the process of basing judgments on empirical observations, then those who argue that we are far more likely to do harm than good when we start to "help evolution along" seem to have the facts on their side.