I think maturity has alot to do with it.
Its have the brains to stop and think and realise that spinning the wheels up, racing the car on the street and just generally acting like a d*ck on the road is not acceptable and if you want to do this, you have to face up to the consequence if you get caught.
While I realise that people more then likely will just mod their car anyway or just drive a v8/turbo, thats their risk to take.
I can certainly relate to people who say that they already drive a V8 or turbo and they are on their P's, as did my L's in a V8, and held my full 2yrs of P's driving a V8 and nvr had a accident and only got 1 speeding fine, but unfortunately not everyone is as smart as some of us, and therefore the government has to cater for everyone.
When it boils down to it, if the government decides to do it all you can do is suck it in, stop whinging about it and just deal with it. Not everything in life can go your way.
2 years of driving a non turbo/v8 or however they want to distinguish it certainly wont do any damage and on the bright side it will save you a sh!t load on fuel! =)