I see what you mean now from this context, thanks for the clarification, however it is just restating that they are denying that they knew of prism, not all allegations. Part of the confusion here is that the slides say one thing, the article summarises it (perhaps loosely) and google denied something else altogether (back door etc). I would note though that the article did not say they had unfettered access via a back door, or root access or any such detail, those are things implied in the google statement, which curiously denied things the article did not allege.

Personally I thought the article did an OK (though far from perfect) job of summarising the puzzling gaps between the slides and the company statements, and didn't imply all the things people have read between the lines, but wish it had gone into more detail, however I don't feel that's a hugely important part of this story. It sounds like we might hear a bit more detail over the coming weeks.