Because the sufferer is back exactly at the state before suffering, without even a recollection of suffering. And all the suffering was merely number multiplication.
This belief is very, very far from mainstream. It implies that suffering is a complete non-issue in general—after all, we all die and at that point by definition don’t have a recollection of prior suffering (or anything, really).
Since “resetting” is equivalent to killing a being and creating a new being in its place, saying it nullifies all suffering already incurred can take you on a very dangerous path.
