This is from the old school of thought on the web, the HTML is only about content and semantics, and all the typography should be left to the browser (and user

This is from the old school of thought on the web, the HTML is only about content and semantics, and all the typography should be left to the browser (and user preferences). If the default font in your browser causes fatigue for you, you can change the defaults. This is hardly possible with most websites now without intrusive browser extensions.