The question Christians need to correctly understand. What is the difference between what is deemed to be a false teaching of Penal Substitution Theory from the Biblical penal substitution?
That is easy.
What you and I are talking about in agreement....what you call "penal substitution"...is God laying our iniquities on Christ, Christ laying down His life for us, Christ ransoming us, Christ becoming a curse for us, Christ being made sin for us, us being healed by His stripes, Christ being the Last Adam, the Firstborn of many brethern, the Propitiation in Whom we escape the wrath to come, etc....that is biblical.
Where things go off the reservation and into philosophical (and unbilical) carnal "wisdom" is in the amalgamation of Christianity with paganism called the Penal Substitution Theory of Atonement.
The difference between what you and I agree upon (what you call penal substitution) and the Penal Substitution Theory of Atonement is the Theory is based on a lie (it is based on a humanistic idea of justice popular in the 16th century). Penal Substitution theorists agree with us, but then they add that Christ suffered God's wrath, God punished Jesus instead of punishing us, sins can be transfered from a person to another person, God condemned the Righteous to acquit the guilty, etc.
What you and I agree on (what you call penal substitution) is biblical. But calling it penal substitution can lead others to think we hold to another gospel by believing the Penal Substitution Theory of Atonement correct.