Lies, damn lies, and statistics.
Usually most of those rejections are errors of some kind.
The real questions are, how many of those people were subsequently approved, and how many people were prosecuted?
Subsequently approved for an error is not always easy or cheap. Burden of proof is on the one denied. A friend of mine went through this. He had to hire an attorney. Total cost was around $2000 and over a year to correct the error..