But that's exactly the crux of his argument - they're not taking anything away, because the things Redis Labs is working on are things that he would not accept

But that's exactly the crux of his argument - they're not taking anything away, because the things Redis Labs is working on are things that he would not accept into Redis itself even if someone were to donate the code for free. The Labs modules only exist because of Labs. Whether you believe him or not is your call, but it's not simply a semantic argument.