Dr. Craig is a good debater. However, I disagree with most of what he said. For example, he said that the existence of God guarantees objective morals. That's not at all obvious to me. God could have simply decided that he wouldn't bother making objective morals. The Deist outlook, for example, is that God set the universe in motion (with physical laws, etc), and simply stands back to watch what happens.
Most of Dr. Craig's arguments seemed to be based on semantics.
God is intrinsically good.
Thus, good must come from God.
That's a simplified version, but captures the circular nature of the argument. I'm not buying it.
The real question is does the absence of God necessarily mean that there are no objective morals. Dr. Craig says "no". I agree with that.
And this is where Dr. Harris and I disagree. He claims that objective morals CAN come from natural causes. His book, The Moral Landscape, tries to make that argument. While I agree with almost everything that he says in the book, I don't agree that there is a universal, absolute way to define good and bad, or right and wrong. One of his arguments asks us to consider the universe with the worst possible misery for everyone. To him, this establishes a global anchoring point, and any move from that universe will result in less misery, and therefor be good. Though I haven't nailed it down yet, I feel that there is something wrong with this line of reasoning. Perhaps it has to do with the fact that -- no matter how bad the universe is -- I can always imagine a universe that's worse.
I cringe when I hear Dr. Harris authoritatively state things like female genital mutilation is objectively and universally wrong. It's not that I think genital mutilation is a good idea... I don't. But my reasoning is not motivated by a universal moral; it's based on my emotions. I would hate to see anyone subjected to that kind of torture, but that doesn't make it objectively wrong. It just feels subjectively wrong to me.
I routinely mutilate the bodies of other living organisms when I eat. Does that make me bad? Should I stop eating? And the rightness or wrongness of killing someone always seems to depend on the circumstances; were you defending yourself? These questions of morals always seem to hinge on your point of view. To me, that suggests that there are no objective morals.