I've heard on a number of occasions people referring to GT5 as a "driving game" and NOT a "racing game". Am i missing something? Are those not racing tracks you are driving on? is there some kind of open world setting to drive around in? Are their paralleled parking challenges at some point? 
 
What exactly do people mean when they say it's not a Racing game?

I spend more time tuning the car than I do racing in races.  Mostly I spend my time on lap times, and tuning. 
 
It's also simulation based.  The goal for people playing GT is different for each person. 
 
So, ask someone who does the racing in GT.

It is stupid when people say that, but they only say it to emphasise the point that Gran Turismo really, REALLY focuses on delivering a realistic driving simulator. Polyphony Digital don't fuck around. There are no rewinds, there's no "make this accessible for noobs" button, there are no gimmicks. Just pure physics rendered as accurately as currently possible on a console. Then they just put a 15 other cars on the track using that driving model and task you with beating them. Truthfully, the racing is entirely incidental to the act of driving the vehicles.
 
But it's still most definitely a racing game.

" It is stupid when people say that, but they only say it to emphasise the point that Gran Turismo really, REALLY focuses on delivering a realistic driving simulator. Polyphony Digital don't fuck around. There are no rewinds, there's no "make this accessible for noobs" button, there are no gimmicks. Just pure physics rendered as accurately as currently possible on a console. Then they just put a 15 other cars on the track using that driving model and task you with beating them. Truthfully, the racing is entirely incidental to the act of driving the vehicles. But it's still most definitely a racing game. "

Gran Turismo is to vehicles what Microsoft Flight Sim is to aeroplanes.  

no, your not missing anything. it's a racing game. i don't understand why people say that. 
 
there are a lot of people that do different things in the game. some people just spend their time tunning the car. while others spend their time racing.

Give me Dirt 2 over this grandpa's game any day. I like my cars just like I like women: huge, dirty, wet, rolling, slow-motioned, and sometimes FLAMING.

GT5 is not the most "hardcore" simulator game out there.
 
That would be one of the GTR games, GT5 is like forza a sort of half watered down sim.

Do real racing driver use GT for practicing? 

You're not missing anything - it's a racing game.

The whole thing looks like some elements are from 4 years ago, that they finished early on and forgot about for a while.

Burnout Paradise is a driving game. GT5 is definitely a racing game.

The AI in a driving game seems to go on a set route and acts as somthing that judges ur performance instead of pure laptimes.
 
The AI in a racing game seems to try to win the race and will change what it is doing as you change tactics.
 
That is why my guess is.