This is a programming term.
When a user tries to make a program do something inconsistent, absurd, or impossible, there are two ways for the program to respond. First, it can crash: This is a sign of what we call "grossly incompetent programming". Alternatively, the program can do very tedious sanity checking on absolutely everything that the user does, and simply refuse to comply when the user asks it to do something stupid. It should refuse politely (the word "dumbass" is deprecated), and with an explanation sufficiently detailed that the user can back up, try again, and get it right next time. This is a "magic middle finger". All the best programs have them, and some of the lousy ones have them too.