I used to set my bike up with front brake to right lever, and a lot of racing cyclists did so. If I remember correctly Campy brake calipers were set up to accommodate that (but probably also due to European origin). When racing one needs precise control of braking, and my right (dominant) hand is both stronger and more coordinated. Also, in an emergency stop the front brake is modulated to prevent losing traction in the rear, and again the right hand is more coordinated for that function. As mentioned above there are multiple reasons that one may choose the more common configuration, and I was too lazy when I got my most recent bike to change everything - it's not as easy as it used to be.