The Blessing of forgiveness is to never have God lay sin to your charge, not ever !
Jesus did not take away the sins of Calvinists before Calvinists were born. Calvinists were not born into a perfect world where sin did not exist among the chosen few Calvinists and assorted elect. Jesus took away the curse on sin that was on the whole world in order that God could justify repentant sinners of their sins without violating principles of justice.John 1:29
The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world.
This is also the World John writes of in his Epistle when writing of the propitiation of Christ taking away our Sins 1 Jn 2:2
2 And he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world.
1 Jn 3:5
And ye know that he was manifested to take away our sins; and in him is no sin.
1 Jn 4:10
Herein is love, not that we loved God, but that he loved us, and sent his Son to be the propitiation for our sins.
Now being the propitiation for our sins, and taking them away are one and the same. His Death was that satisfaction to Gods Law and Justice to take away our sins, and that could not be the case if were not absolved of, acquitted from, justified from them all before God. Doesn't the resurrection of Christ testify the same Rom 4:25
Who [The Lamb of God] was delivered for our offences, and was raised again for[because of] our justification.
So that World in Jn 1:29 is a Justified world with no sin charged to it 2 Cor 5:19 because they've been taken away, so it cant apply to all without exception ! Some will yet die in their sins Jn 8:21,24