Greetings in that Divine and Most Precious Name of Our Lord and Savior Jesus Christ!
We in Orthodox can't accept Penal Substitution or Atonement theories because they are too legalistic for our tastes.
I doubt that you really mean "for our tastes", for I am sure you agree that truth is not tailored to our tastes, but antedates and supersedes them. Anyway, be that as it may, I want to home in on your use of the word "theories". I prefer the word "teaching", but let us also leave that aside.
If our "theory" of penal substitutionary atonement is incorrect, or if your - dare I say it? - "theory" of the Blood, and thus the virtue of it, being received at the Lord's Table, is incorrect, does it not remain true that your theory and ours both move us to trust the benefits of Christ's death alone for our rdemption? I sometimes preach that it is not our understanding of how Calvary worked, but our trust in the fact that it did, that saves the soul.
I am sure that both 'theories' can lead to an empty religious practice without faith, and Evangelicals form an impression of Orthodox thinking they will be saved because they take Communion (sort of, ex opere operato
). I believe you would strenuously deny that such is the true nature of your religion: are you not taking Communion because you believe that "the blood of Jesus Christ cleanses us from all sin"? And have you not thus attached, to your trust in the power of the Blood, a theory about how it works?
Well, you may say that we do the same: that we trust the shedding of his blood, and we attach a theory about how it operates. Our "theory" has helped untold thousands to reach a point first of despair at ever being able to overturn the effects of their sin, and then to a point of placing all their trust in the Son of God, "who gave himself for me" as it is somewhere written. Consider the popular hymn Rock of Ages, cleft for me
Nothing in my hand I bring,
Simply to thy Cross I cling
Finally, we are not unaware of the passages in John 6 and perhaps elsewhere, which lead you to your eucharistic beliefs; surely, you are also aware of the passages in scripture which lead to our belief in penal substitution as the means of the Atonement? But do we not all both love and trust the One who died for us?