It has nothing to do with driver ratings, gate keeping or anything.
Driving styles of players are vastly different and just because a lot of top players are fastest in car x that doesn't mean that you, me, or anyone else won't be able to be faster in another car that fits ones driving style much better. And unless you're one of the best players the difference in driving skills will always have a greater effect than any differences in BoP will.
But it seems redundant to even try to explain it when you're throwing around poop instantly