Evidently because a large enough number of people hadn't seen this before, found it interesting, and upvoted. Is it really so difficult to understand? Even though there's "news" in the name of this site it doesn't mean that everything posted here needs to be straight off the press. It gets upvoted to the front page if there's a large enough audience for it.

No idea why you’re being down voted. I don’t see any significant change from the WWDC demo months ago so this can hardly be called a ‘reveal’