There are no writings refuting Penal Substitution Theory prior to the 16th century because the theory was not invented until that time. BUT the writings that exist DO refute necessary elements of Penal Substitution Theory.Right. But let's be honest. The fact is there are no writings refuting penal substitution because it was not discussed as a coherent theory. So what you are talking about is where some early church father writes something about atonement and you take that to refute penal substitution even though there is no indication they were doing so. Yet you reject all the theologians who say they do see penal substitution in the writings because they do not specifically say they are talking about penal substitution. You have a double standard there.
What you're doing here is patently ridiculous. Can you produce one person who espouses penal substitutionary atonement who does not believe one must be born again? That's a false dichotomy with no examples anywhere to be found. You have brought up my objection to Owen and all the limited atonement guys and my answer would just be that penal substitution potentially takes care of one's sins, for those who come to Christ. He can be just and the justifier of all who do because of the fact that he bore all the sin of all the world. I believe in a universal atonement and I believe it is not actualized until a person comes to Christ.
I'm not defending Owen here but he said the same thing, except that in his Calvinistic determinism he honors the inevitability of something God has decreed as being a sure thing, yet not actually done until it is done. So a good Calvinist has no problem with someone being lost until they are saved while at the same time the atonement effectively accomplished what it needed to for all the elect at the time of the cross. (ie, If God says I will do something next week I will infallibly do it with no chance of not doing it - yet it's not actually done till it's done.) The elect are indeed, infallibly "elect" but are lost until they are saved. See R.C. Sproul.
Of course. And I think penal substitution helps explain how this is done so that God can maintain his own honor, vindicate his promises of judgement, remain perfectly just, and still forgive people like us. This is the precise point where every other "theory" fails to be complete.
That said, this itself does not disprove the theory. Christians up to the sixteenth century could have gotten it wrong. What disproves Penal Substitution Theory is the fact it is not in Scripture and what is in Scripture offers a different gospel.
But you believe what you want to believe. I suggest you go back to Scrioture itself (without using the Bible to support any view). But I'd never demand it of anybody. Every one has to live or die with their own choices.