Gregory Nazianzus and Penal Substitution

I was particularly shocked to see the writers of Pierced For Our Transgressions include Gregory Nazianzus (an archbishop of Constantinople in the fourth century AD under whom the Nicene Creed was finalized) in their list of Penal Substitution advocates. There is a particularly famous passage in Gregory's writings rejecting a form of the Ransom from Satan view (highly unusual in this period, and interesting because his friend Gregory of Nyssa endorsed the form of the Ransom from Satan view being here rejected) which also equally rejects out of hand in passing any type of Penal Substitution:

We were detained in bondage by the Evil One, sold under sin, and receiving pleasure in exchange for wickedness. Now, since a "ransom" belongs only to him who holds in bondage, I ask to whom was this offered, and for what cause? If to the Evil One, fie upon the outrage! If the robber receives ransom, not only from God, but a ransom which consists of God Himself, and has such an illustrious payment for his tyranny, a payment for whose sake it would have been right for him to have left us alone altogether. But if to the Father, I ask first, how? For it was not by Him that we were being oppressed; and next, On what principle did the Blood of His Only begotten Son delight the Father, Who would not receive even Isaac, when he was being offered by his Father, but changed the sacrifice, putting a ram in the place of the human victim? (Orations 45:22)

From elsewhere in his writings we find out that Gregory Nazianzus held a combination of Moral Exemplar, Recapitulation and Christus Victor. Gregory was also a strong advocate of Origen's theological views, and these included the view that God only ever gave punishments for the purposes of morally improving people (thus, Origen's view was that hell was not eternal and comprised sufferings inflicted to achieve moral reform). Obviously such a view has incompatibility problems with Penal Substitution. Gregory, in this vein, comments:

it is in mercy, I am persuaded, that God inflicts punishment. (Or. 45:8)

Not only is Gregory a theologian who explicitly rejects penal substitution, not only does he hold well developed views of the atonement that are not penal substitution, but further to this, penal substitution is incompatible with his other theological beliefs. Knowing this, I was extremely surprised to see Gregory Nazianzus' name on the PFOT list of people who taught penal substitution.

The quote of him that these writers claim proves he taught penal substitution seems random. Gregory talks in this passage about Christ saving mankind, but doesn't explain here the mechanism by which he thinks this worked. As I mentioned, he makes his views on the mechanics of atonement clearer elsewhere. So the quotation of this passage as proving Gregory taught penal substitution strikes me as just bizarre. They are once again claiming penal substitution is taught by an ancient theologian who just doesn't teach it.