I think they even said in the keynote that they would be accepting community changes ("pull requests" in GitHub terms), so I'm not sure why the article doesn't have any reference to what was stated by Apple officially. Seems like FUD to me, but I could be wrong.
The article also states this: "Apple stated, "Contributions from the community will be accepted -- and encouraged."
The question is what does that really mean?
Apple has open sourced a lot over the years http://www.opensource.apple.com/ I don't understand why everyone acts like this is the first thing they've ever open sourced.
The article cites such examples as Darwin, Webkit, and CUP--and what Apple has, and hasn't, done with them.