I don't think Apple was ever denying that there was a problem with the PowerBook screens -- it's just in Apple's best interest to make sure they know the EXACT problem and solution before talking about it. Just because they release a knowledge base article outlining the problem doesn't mean that they just recently "acknowledged" the problem. They just wanna be sure of the problem and solution before spreading panic. That's a common business practice.
The release of the knowledge base article just means that they've found a specific problem with the screen AND a definitive solution to the problem.
Sure, the employees at the Apple Stores would probably tell you there's nothing wrong... they're too low on the totem pole to say what's wrong and what's not with a newly released piece of hardware, but now they can say for sure if something's gone awry and the proper steps they need to take to remedy it.
It's not like Apple was ever ignoring the users with the white spots or telling them to take a hike because nothing was wrong.
