Because most of the Win32 subsystem operations have been moved to kernel mode drivers, in Windows NT 4 and later CSRSS is mainly responsible for Win32 console windows, GUI shutdown, and threading. It is critical to system operation, therefore terminating this process will result in a Blue Screen of Death.
_Rolling_On_The_Floor_Laughing_My_Freaking_Hindend_Off_.
Well, I always figured that Microshaft(tm) didn’t share my belief that no user-visible program should be able to take down the Operating System, other wise it wouldn’t be so easy :-D.