Well, the problem is that that
is the default size -- every major browser's default font size is 16pt -- but since web developers tend to be younger people with better vision, most of them decide to take control away from the user and force the font to be smaller, which is why major browsers have now largely abandoned the "change font size" feature and instead switched to the "zoom the whole page" feature so that people with less than perfect vision can actually read stuff without squinting from 3 inches off the monitor.
On top of that, the default text size on WoWI is a certain size. People like me who use accessibility features like page zoom have the zoom level set to a certain level for the site to make the text comfortably readable. If your page is suddenly 20% smaller, then we have to spend time changing the zoom level to read your page, and then changing it back to read every other page on the site, and that's just obnoxious and unnecessary.
That's why I suggested that if you find the default font on WoWI to be too large, you just use your browser's zoom feature to make it smaller across the board, instead of making your page a different size than the rest of your site and inconveniencing everyone else.