placing the links at the bottom is very bizzare and not a great improvement to accessibility because nobody in the world expects those links there and its hard to even scroll there. If one is worried about accessibility maybe have both, why not, because I found the footer to be less intuitive and convenient.
It's easy to scroll there. Just click the link at the top. Did it on my 10 year old mobile phone and it worked.
The blog post says users are conditioned. That's exactly the problem. The author hopes that users would be conditioned to find a site map at the bottom. I have the feeling 15-20 years ago in the ages of pure HTML that
was more common. Nowadays 99% of the users don't learn that. It wouldn't be hard or impossible to learn. It's just that marketing driven design for fancy UI has ruined accessibility because those user have no voice.
I read that part, but I don't think trading off massive amounts of usability for the majority of people to slightly increase the usability for the minority is the right decision in almost any case.