that's for the visitors of w3schools, which are more technical people. my mom, who would use IE if it wasn't for me tricking her into using firefox, would never be a w3schools visitor.

from the bottom of the page: W3Schools is a website for people with an interest for web technologies. These people are more interested in using alternative browsers than the average user. The average user tends to use Internet Explorer, since it comes preinstalled with Windows. Most do not seek out other browsers.