That’s right.
Basic tenet of the FDA (and USG, therefore) is FDA does not tell doctors how to practice medicine.
FDA determines that drugs are safe and determines efficacy for given indications.
An approved drug is safe under indicated usage. A doctor can prescribe an approved drug for anything under the established usage.
So, it’s NOT up to the FDA, but individual states then. Ohio just BANNED prescribing HCQ for Covid-19 this week and I don’t think the FDA can do a damn thing about it.