disclosing information is not a medically neutral act. Knowing you have a medical condition can create a great deal of anxiety and anguish and prompt lots of tests. If the result of all those tests and anxiety is "no action indicated," you've basically given your patient a condition that reduces their quality of life for no upside.

I once had a misdiagnosis of an incurable illness that I didn't actually have, and the stress of dealing with that caused me to develop another, very real medical condition that took a year to get under control.