All of you need to take a deep breath and stop guessing about the legal protection of confidential information.
The Intel Confidential phrase is almost surely embedded in the PowerPoint template used to make the slides. When developed and first presented the presentation was probably considered confidential. Handouts are routinely converted to pdf format and the posting by HP is a pdf document.
Intel can at a later time can release the confidential classification. Voila, what was confidential is now not confidential. HP may even have asked for and received permission to post the material on its web site. It is not a big surprise that the Intel Confidential label was not removed from a pdf document.
The material in the presentation is not high value stuff. To draw comparisons with red book and yellow book material does not make any sense. The values of the contents are entirely different.
Note that much of the material in a yellow book is revealed when a product is released in documents such as hardware and software reference manuals.