yours must have been modified then I presume.
I guess the start in 2nd gear saves a little on fuel or maybe wear and tear?
I'm glad I got the 1st gear start, I actually didn't know about the different gear starts before i bought the car, or auto boxes in general, being used to driving a manual car.
If my driving instructor knew I was driving an auto (and a German one at that) he'd be using some very colourful langauge in his Renault Megane.