When menopausal women take synthetic estrogens in order to stave off heart disease...
Granting your premise, then in this case, can the medication be properly called "birth control," since the primary objective is "staving off heart disease"?
My assertion regarded "the pill" when it is used as a method of birth control, which is by far its most common use.
In fact, "the pill's" usefulness for treating disease is extremely limited, according to the opinion of doctors that I trust.
And caffeine when it is used as a method of sleep control, which is by far its most common use.