Quote:
I guess one way to look at it is that it's like a shunt for the electrons instead of an on/off valve.

Perhaps a better way to look at it is that of a voltage divider. You get the full output voltage of the driver stage over the full resistance of the pot, but the centre tap taps into it at a variable point - exactly halfway it gets exactly half the voltage (assuming a linear pot and no influence from the imput impedance of the following stage, but...)

Quote:
It seemed to me that wiring all three pins like that *WAS* shorting the inputs.

Indeed, but for most *input* stages that is perfectly OK.