I have to say, I'm rather disappointed with Dawkins in this interview. But at least he has the intellectual integrity to admit that he's just lazy and conformist when it comes to eating meat, and doesn't try to offer an elaborate justification for ignoring the moral legitimacy of the animal rights argument.
The closest he comes is to compare meat-eating with slave-holding, in the sense that many obviously moral people during slavery days held slaves out of social convention, even though they knew it was wrong. The problem with that argument, though, is that meat-eating is far less of a socio-economic "necessity" than slavery arguably was for some slave-holders. Slave-holders faced (or reasonably believed they faced) real economic consequences for themselves and their families by emancipating their slaves. Meat-eaters have no such obstacle in their way; aside from farmers and ag-business types, no one's livelihood depends on meat-eating. So, Dawkins' argument here is even lamer than it sounds at first.
Singer is spot-on, I think, that Dawkins (and by implication, most other "evolutionists") clings to vestiges of religious belief about the specialness of humanity as a way of justifying the eating of animals to himself. I wish he had pushed Dawkins a bit more in this point, but it was Dawkins' show, not his.
On the whole, though, this is a fascinating interview. Pencil it in.