Seeing one of the opening paragraphs say "The right font choice along with the absence of sidebars and popups makes everything feel easier and better to read" while being distracted by the bloody sidebar and ad on this site is rather interesting.
The original article appears to have been posted on the author’s blog quite some time ago: https://ooomf.com/blog/the-science-behind-fonts-and-how-they...
As such criticising contradictions between website design and what the article advocates makes even less sense than it usually does.
I do think there is still more handwaving in the article than I'd care for. In very few cases was it a small change in font that made a difference. And, even then, it is still artistic in nature. Pretty things make people more trusting and happy. Some fonts are prettier than others.