You must be kidding me ? The sins of those Christ died for !
No, I’m not “kidding” you. (and no, the subject of propitiation is not sin).
“He Himself is the propitiation for our sins”
Propitiation carries the sacrificial imagery from the Old Testament. Sin is not the object of propitiation – Christ is the propitiation for our sins.
In the Old Testament sacrificial system, the offering was made before the Lord as a propitiation: “the priest shall burn it on the alter on top of the offerings made to the Lord by fire. In this way the priest will make atonement for the sinner for the sin he has committed, and he will be forgiven” (Lev. 4:34). Interestingly enough, in the Old Testament sin is never the subject of propitiation either. Propitiation is the sacrifice which appeases God through which sins are forgiven.
Propitiation is the action of appeasing. Christ did not appease our sins, but was instead the appeasement for our sins.
Like I said (and you confirmed), we are in agreement concerning the elect, the non-elect, and God’s wrath in regards to Christ as the propitiation for our sins. Where we seem to disagree is in examining the biblical texts.
If you don’t have one, I’d suggest purchasing a good interlinear New Testament, a lexicon (I like Perschbacher’s), and a concordance. Choose good commentaries by scholars in the field of hermeneutics. A good one will provide various ways a passage may be interpreted and weigh the strengths and weaknesses of each. Unlike commentaries written by pastors, these attempt to interact with the text apart from theological presuppositions (although many will also offer why they believe a particular interpretation is better). If you do have them, I'd suggest using them. Word studies are not only important, they are also interesting.