The entire premise of this article is predicated upon the assumption that the user takes some stupid action (like executing an attachment from an email).
The problem with Windows has always been more than just stupid user actions. Windows has been vulnerable to viruses, worms, trojans, malware, etc, without the user taking any stupid actions at all.
Exactly. This shows that there is a difference between POSIX-based systems and Windows-based system at a technical level. The lack of virii on Linux/OSX is not due to their lack of popularity, but to fundamental design differences.