They're not racers is the only explanation I can think of. The 0 Mile people that is, they're like model collectors, rather than racers. Reality is, if your going to race the cars, they're going to clock up miles.
This freshness supposedly making cars faster is ridiculous, or I haven't seen any evidence of it, and I do a great deal of online racing, and have an extensive garage, and doubles of cars, some zero miles, some lots of miles, I can't detect a difference in them. I sure people will insist there is a difference, but then again some people believe in little green men in ufo's.