"Subjective Judging" is a bit of an understatement. If I take my car to a real car show, where points awarded for restoration is taken very seriously, there is no reason to enter my car. I'm pretty sure that the award plaques from Quaker Steak and Lube or Hooters wouldn't impress anybody.
On the other hand, I avoid the heartburn that comes from having someone scrutinizing my car for things like dust on the frame rails.
Rust is bad news on any car, but there is no such thing as "rust free". These cars came from the factory with surface rust already starting. They were taken off the line and parked in an unplowed parking lot in the middle of a Michigan, Ohio, New England, etc. winter. Then they were shipped in open rail cars or truck carriers to sit in a dealers parking lot until they were sold. After that, you had the option of a Ziebart treatment to rustproof your car, but even if that worked, it still has to be removed to restore the panels back to bare sheetmetal.
You can't win for losing. I've been told that sand in a bodyshell can be just as much of a pain as rust is.
Point is that hard work and attention to details is what wins shows, but pride of ownership is what the hobby is all about.