Well, that's true, but the fact that he said, "I'll only do it if they air it unedited!" makes me think he thought they would say, "no," and he'd be able to decline while saving face. My gut tells me he'll make up another excuse now. I'd love to be wrong, though!
I would have loved to see that fight happen. Both are human garbage, but Zuckerberg is apparently a high level BJJ competitor. I think it would have been pretty one-sided.