Why is it so important for you to believe that Christ's petition was not answered?
Because the only alternative -- to disavow the rest of the Bible with respect to forgiveness of sins -- is unreasonable. No passage of Scripture stands alone. The proper way of interpreting Scripture is in the light of the rest of Scripture. So, if verse A seems to say something, but verses B, C, D, E, etc say something (apparently) to the contrary, the A must be understood in accord with the rest. You have not offered any response that accounts for all the other verses I mentioned (and I could mention many more).
Why is it so important for you to believe that -- based on one verse -- this sin was not charged to those who ultimately may not have repented and turned to Christ for forgiveness of all their sins?