Dr. Craig is a liar.

[SteveII]

None of what you said matters to asking the question whether the universe (or its predecessors) existed necessarily or contingently. Carroll seems to think neither--that the universe (or the quantum vacuum and its associated laws) always existed unexplained.

So, how is Carroll's view not: A) If atheism is true, the universe (or its predecessors) has no explanation of its existence.?

And that being logically equivalent to B) If the universe (or its predecessors) has an explanation of its existence, then atheism is not true.

B
I'll put it plain and simple, you asserting that somebody said or implied X does not mean they said or implied X, especially when, like in your current case, you've absolutely no evidence to support this assertion.

As I said your premise is pure bullshit, because it posits a unified mind for all atheists which is false, and then when you try to row back and lyingly claim you were talking about one man, you still managed to put words in another person's mouth.

I, in turn, will try to be clearer: 

1) Carroll does not believe in God.
2) Carroll said the universe (or its quantum vacuum predecessor) always existed for infinity with no explanation (because he does not believe in God). 
3) Carroll said the universe (or its quantum vacuum predecessor) could have failed to exist and he could conceive there there could have been nothing.

How did I mis-characterize his position: A) If atheism is true, the universe (or its predecessors) has no explanation of its existence.? Are you saying he must have meant something else? 

Further, how is this a mis-characterization of other atheists? Do some believe that the universe (predecessors) has an explanation? What is it? Do some believe that the universe (predecessors) necessarily exists? On what basis? 

Finally, if you can't avoid A), and B) If the universe (or its predecessors) has an explanation of its existence, then atheism is not true, is logically equivalent to A), then both statements are true.