I always want medical providers to have access to records from other medical providers. This saves me time and money, and helps ensure more accurate diagnosis and treatment.

And it surely IS the standard of care. A therapist who didn't check on your past treatment, possible drug reactions, etc. might well be considered negligent. Patients don't always remember or accurately report these matters.

I don't understand the objection. If you want to hide something from your current therapist, then you're just wasting your and her time.