There IS NO Pin 14 on an Uno!. There is Digital Pins 1-13 and Analog Pins A0-A5.
There is a digital pin 0, too.
By your logic, when the user chooses to use pin 6, the Arduino should tell him/her that is D6. Nonsense. The analog pins can be used as digital pins. That is clearly documented. The next pin after 13 shares the same physical space as analog pin 0. Why should there be any mystery about the fact that pin is numbered 14?