Though no official statement from John Carmack accompanied id Software's GPL release of the Quake III Arena source code (story), id's Technical Director did make a couple of posts to the Slashdot story about the release.

Besides a quick thank you and another quick opinion on GPL/commercial release thing there's also a post about the assembler code in the source where he recommends that anyone working with the Q3A code should just delete all the asm for maintainability before going into a bit of detail on the pros and cons of its use in the first place and its lessened applicability today.