As the OP stated, because it's not a TV show; it is news. Unlike TV shows, news is widely disseminated to the public. Even before WWDC ends, every news outlet, website, blog, forum, etc is going to publish every detail.
Making a major news event "spoiler free" is silly because you would need to lock yourself in an underground bunker to avoid hearing of it until some point in the future when you wanted to take it all in as if it was "new."