It is not a pelagian fable that those who depart this life with original sin only (i.e. unbaptized infants) are condemned, but without the punishment of fire. Pelagians were also wrong that there is a place between Heaven and hell free of guilt and punishment.
This is an infallible quote by Pope Zosimus (confirming Canon 2 of Council of Carthage):
It has been decided that, likewise, if anyone say that it might be understood that in the kingdom of Heaven, there will be some middle place or some place anywhere infants live who departed from this life without Baptism, without which they cannot enter the kingdom of Heaven, which is life eternal, let him be anathema. For the Lord says:"unless a man is born again of water and of the Holy Ghost, he shall not enter the kingdom of God"
This is the same Pope, St. Zosimus, who also said "
No one of our children is held not guilty until he is freed through Baptism".
Also from this infallible pronouncement:
" The punishment of original sin is the loss of the vision of God; the punishment for actual sin is the torments of everlasting Hell".
We can deduce that those who die in the state of original sin like unbaptized infants do NOT see God, as they incur the "loss of the vision of God"; but because these babes do not have any actual sin, then they do not have any "torments of everlasting Hell".