Why would you write..

So if you’re not going to hire a guide, my big Machu Picchu tip is that you probably should buy / rent a guidebook before you go and take it with you. I would imagine such guidebooks are pretty prevalent.

when it's mandatory to get a guide? Why even suggest that there is an option not to get one?

Also, the 45 minute hike isn't where you get the "classic" Machu Picchu photo. The author is misinformed and is giving out bad advice and information.