@dkranzberg That article actually falls on both sides of the fence several times:
In traditional printing serifed fonts are used for body text because they are considered easier to read than sans-serif fonts for this purpose.
That backs up your argument. But then the article goes on to say:
However, the belief isn’t supported by scientific study. Studies with child participants have found no difference in their ability to read either style of typeface. Sans-serif fonts are more often used in headlines, headings, and shorter pieces of text…
In addition it is the opinion of many modern font foundries that serif should be used for headings, and sans-serif should be used for body copy.
The font foundry Hoefler & Frere-Jones and many other widely respected industry figures have long supported this approach, as you can see from their website and work.