So are you trying to be obtuse? Or are you really that slow?
That's like me saying I accept the fact that with OSS you can change the code to do what you want, but only if it's widely available and won't affect anything else.
Now how silly is that statement?
We are talking about the inferiority of the Windows password system. No matter how many theoretical (your case) or actual add-ons there are, the capabilities of Windows' password system as shipped and as used by all (or almost all if you can produce your plug-in) Windows users are inferior to those of Linux systems as shipped by all major distros.
It's a simple fact. Admit it.