Institute of advanced wheel shufflers!

Push pull was devised from a time when there was one turn from lock to lock. I once had a drive of a 30's Morris 8, I nearly turned the bugger over when I got to the first corner because I tried to turn the steering wheel as far/fast as I would've done with my 'modern' Mk III Cortina of the time.

do they still teach that? most pointless thing ever 
I might be wrong, but I thought it was pull push 

Pull-push, like the majority of Roadcraft, is designed to be an easy-to-apply, easily remembered base for drivers to learn. Remember it was first devised for police drivers in the 50s, and is still taught now - the majority of whom have no interest in the finer points of driving.
Pull-push isn't the only way to steer, I prefer to use (and teach) it as the first of many tools in the box, including fixed-grip and, shock horror, crossed-hands rotational steering. Each of which have their place. If you come across an observer who thinks PP is the only way... find a new observer.