Do you refer to the better availability of games on Windows? Are games good enough a reason for you to stick to that OS even when doing work?
I can sort of relate to you. I have a dualboot Windows system, where the Windows part is for gaming only. It serves roughly the same purpose as many people's gaming consoles do, I don't even try to do work with it.
There is software I want to run natively (like games) that only runs on Windows. It is an indisputable fact that this is the common case. It is not irrational to want to run some of this software; it's also not irrational for someone else to not have that desire, but that's not the point here.
There is no software I want to run natively that only runs on OS X or Linux. The software that doesn't run on Windows is software I don't need to run natively; I can SSH in to a Linux server or VPS somewhere to test/manage/deploy it.
So the rational choice is to run Windows as my native OS.
If you are not satisfied by this argument, then I don't think you're being truthful with yourself regarding the "I have yet to meet the Windows user who can rationally reason about their choice".
I am a Linux developer. I have set up, administered and deployed software on Linux stacks for almost 20 years. But I don't need to be booted onto a Linux OS to do any of that work -- Python, PHP, Apache, MySQL, subversion and git all run fine on my Windows machine alongside my editor for dev and testing. I can SSH in to any of the Linux machines to administer and deploy on them just as easily as someone running Linux natively.
To force myself to run Linux and reboot into Windows to use the Windows-only software would be entirely irrational. Why would I waste my own time like that?
As opposed to?
Do you refer to the better availability of games on Windows? Are games good enough a reason for you to stick to that OS even when doing work?
I can sort of relate to you. I have a dualboot Windows system, where the Windows part is for gaming only. It serves roughly the same purpose as many people's gaming consoles do, I don't even try to do work with it.