He's just saying that in real life you don't always watch a race with crystal clear atmospheric conditions, for instance. Sometimes, light overexposure or a bad adjusted focus of the lens doesn't help to achieve the best image quality in the recording/broadcasting/photography of real races.
He's not saying that GT5 graphics look more real than reality.
"I think that I don't think."
- Soli Deo Gloria -
The FUTURE is the FUTURE. Now... B_E_L_I_E_V_E!