(I wont insert Craigs argument since you found it erronous).
I do not necessarily find it erroneous. I find it relatively weak compared to other arguments.
As for me, I believe that God is the ultimate source of everything.
Since everything means everything, this, of course, includes moral truths that we both hold as true and agree upon.
I think evolution can explain a great deal of our morality, and perhaps even all of it, although I have no proof of that either.
Bohm could say that what we regard as moral law is natural for successfully cooperative, intelligent life like our own.
I would agree.
BTS