Aren't heads of state civilians too?
Most head of states of countries that are not military dictatorship are civilian, i.e. they are not military, but if they rule over the military (such as the American president who is commander in chief of the military) does that count as being treated as a civilian for the purposes of wartime policy?
A similar role was played by Khamenei who was commander in chief of the Iranian armed forces.
Netanyahu is also a civilian and nevertheless the ICC issued an arrest warrant for his responsibilities for the behaviour of the IDF in the war in Gaza.
The formal definition used by the ICC is "civilian superior".
"To initiate a war of aggression, therefore, is not only an international crime; it is the supreme international crime differing only from other war crimes in that it contains within itself the accumulated evil of the whole."
There can be an innocent civilian and a civilian held responsible for ear crimes, when such civilian acts as civilian superior of the military
Words are complicated and interesting because of that.