Ummm. Jesus is.... God.
He is judge, jury and executioner. If he asks for your forgiveness, it is done. Period.
The Jews who delivered up Jesus to the Romans and the Romans who carried out the sentence will not be judged on those specific deeds (unless you believe Jesus lied in a moment of weakness). He will remember them no more. It is for their other deeds that they will have to answer.
Of course the verses taken all together do not say that. Any putting to death the Son of God was one of their deeds.
If he asks for your forgiveness, it is done.
He merely asks. It's important to note that Jesus did Not say, "I pardon you all of this sin," which is the way you apparently want to read the verse. Just as He elsewhere states, "Father, if it is Your will, take this cup away from Me; nevertheless not My will, but Yours, be done." Wasn't Jesus also God when He spoke those words?
You're ignoring that fact that Jesus was not acting as judge when He hung on the cross. That was for another time.
"The God of Abraham, Isaac, and Jacob, the God of our fathers, glorified His Servant Jesus, whom you delivered up and denied in the presence of Pilate, when he was determined to let Him go. But you denied the Holy One and the Just, and asked for a murderer to be granted to you, and killed the Prince of life, whom God raised from the dead, of which we are witnesses." (Acts 3)
Peter does not absolve them of their responsility. He does not preface his remarks with, "I know Jesus pardoned y'all from the cross, ...". In fact he used the matter of their judicial guilt to preach the gospel, to which many responded. Those who did not would be judged to that sin and many others.