Good question! I never thought to ask where that usage came from.
"Indicated" is an absolute term - either something is appropriate under a given circumstance, or not. "Contraindicated," however, has degrees: some things are absolutely and others only relatively contraindicated, depending on the balance of additional risks and benefits. Sometimes the cure is worse than the disease, in which case that cure is containdicated.
Something that is considered absolutely containdicated should not be given under any circumstances, because of a great probability of causing great harm; an example would be giving penicillin again to a patient who has survived an anaphylactic reaction to a previous dose. Even if that patient had, say, severe and life-threatening pneumonia, and penicillin might cure it, we wouldn't use it but would try to find something else that would work. Absolutely contraindicated.
On the other hand, if Coumadin (warfarin sodium) is given to retard clotting, and aspirin makes that tendency greater and could provoke unwanted bleeding, there may be circumstances in which Coumadin has proved to be insufficient to provide the needed protection. In that case aspirin would be considered only relatively contraindicated and might be given anyway, if the risk of clotting was high enough.
It all depends, as usual, on the word "relatively." Relative to what? Risks vs. benefits, always risks vs. benefits.
None of which, of course, sheds light on the origin of this particular usage of "indicated." I would contrive it to mean that among all the choices available, this one can be designated as an appropriate one.
