Nobody owes you their site behaving a certain way on your phone.
The tone of your opening sentence fooled me then.
> why not make it more accessible?
Maybe because he doesn't give a shit about mobile users.
For what it's worth, his website works better with my screen-reader than most modern-style websites.
FWIW I loaded the article on my Pixel 2 and it looks fine. In the Chrome browser if you double tap on the article text it zooms in to the article.