That is
outrageous!!!
Tell them any attempt to access your records without your express "voluntary" written permission on an individual case by case basis will be met with legal action.
If you tell the company you expect to be off for "approx XXX number of days" based on the info you have of your condition and expected recovery time, that's it, all they need to know.
Yeah, I bet they went to get legal counsel and "clarify" their position after stepping right into it.