Obviously, you don't have to reveal this information if you don't want to, but what kind of medical practice do you work in?
Keeping in mind, the denial rates cited don't mention whether they were passed on to the patient or not, they're simply "here's the number of claims submitted; here are the number that were rejected".
A personal anecdote I've shared on here before (and don't mind sharing again), is that when my Dad (who passed away a few years back from cancer, that could've been treatable in the early stages, but that was his mistake) was insisting on going to an "alternative practitioner" (it was a guy who was a DC, which is why I have a chip on my shoulder about chiro-quackters), it wasn't the insurance company that screwed him, it was the practice itself.
They take a person who's maybe not thinking clearly (who would when they found out they had cancer), gloss over the forms to get them to sign on the dotted line, and then offer reassuring statements like "I don't think we'll have any problem getting this approved".
They were submitting no less than a dozen things per week (every quack "treatment" in the book), and when the monthly bill came in, it was a
"Yeah, we submitted $3800 worth of stuff to them, they paid for $200 of it, they said the rest wasn't covered, but negotiated the remainder down to $1800....due by the first of next month"
That wasn't the insurance company's fault.
Where I think we'll likely agree, is if these insurance companies want to set the record straight, they just have to make certain pieces of data public. I don't doubt that they're denying some stuff that should be approved, and doing that in the name of profit... I'm not naive. But I also don't think "Company XYZ has a denial rate of 20%" is necessarily painting a full picture either.