The demand that Stef debate William Lane Craig has nothing whatsoever to do with a search for the truth, the advancement of philosophy, or even the desire for a good debate. It had everything to do with guilt, self-attack, and insecurity -- and the desire to project it into the most moral target available. Which, for the author of that "request", was Stef, in that instance.
As an aside, I think it's entirely apropos that the attacker chose mister Craig as the hammer with which he tried to beat Stef over the head. If you know anything about Craig's "debate" style, and the odiousness of his interactions with atheists (see: the televised "debate" with Antony Flew, for example), then it should be pretty clear.