There are a number of readings of the Patristic literature, some arguing that the Early Church held to penal substitution, and others to the contrary.As is obvious, there are differing views as to the origination of the doctrine, meaning your claims are false. The reality is that there were various strands of "penal substitution theory", under different names.To take patristic examples from among the Latin Fathers, St. Augustine writes that "by His [Jesus'] death, the one most true sacrifice offered on our behalf, He purged abolished and extinguished ... whatever guilt we had." This is one of several strands of thought: he expounds the mediating work of Christ, his act of ransoming humankind and also the exemplary aspect of Christ's work. As with his predecessors, such as Justin Martyr c.100-165 and Gregory of Nazianzus the imagery of sacrifice, ransom, expiation, and reconciliation all appear in his writings -- all of these, however, are themes embraced by other atonement models and are not necessarily indicative of penal substitutionary atonement.
The primary reason for these differences is that the Church Fathers were trying to reconcile the ideas of Jesus' atoning for another's sins as going against the very principle of justice. Some Church Fathers did not want to conceive of it as "payment to God", bot "ransom". For example, Athanasius argued, per the article, that death and corruption are a necessary result of sin, and the sacrifice was the 'necessary' condition to remove these effects.
In this case, one is essentially denying the principle of 'forgiveness' altogether, as well as destroying justice, which is the very basis for the claim that the sacrifice must occur in the first place. One may ask, what is the origin of this alleged 'necessity'? If God is, then the implication is that God is DICTATED to have to allow corruption and death as a result of sin, and cannot forgive the sin, so one has rendered the concept of forgiveness absurd. Further, the ransom is that God places the burden of the sin on Jesus, not man, meaning justice is not preserved at all, for somebody else bears the burden of a sin of another.