As TFA notes, this may involve repeated resets during boot, added hardware and a whole lot of steps my mother wouldn't take. She'd just be coerced to use Windows.
I find it hard to believe that there are a lot of people who are tech savvy enough to be able to install, partition disks and configure Linux and bootloader on a Windows 7 machine, but are suddenly unable to turn off one setting in the BIOS setup on a Windows 8 machine. And to enable them, we need to make every Windows PC insecure by default and leave hundreds of millions of people vulnerable to undetectable bootkit viruses?
There are lots of Linux distributions (for instance, Ubuntu) that makes all of that very simple. Some of them will even install inside of a Windows partition, or resize it for you.