He made it clear that he won't use any of the code from elsewhere, it's an not-invented-here syndrome on steroids that will result in lots of lost time. :-(
The way I see it is he's just trying to be extremely cautious about legalities. Which should always be fair but especially when you're dealing with a corporation like Apple. It sucks that it hurts collaboration but I find it astonishing that people are trying to blame him for it when all he wants is to protect himself legally.
> then he argues that anyone shipping source in tarballs is noncompliant:
I think he might be referring to the section 2a of GPLv2 (5a of GPLv3) which require keeping track of modifications to the source code. I've never seen this clause being enforced, though. (IANAL)
I also wishes there were some sort of collaboration rather than an outright dismissal.