John, it seems to me that it’s a little more complicated than that, and perhaps it might seem that way to you as well after considering Church law.
The poster only said “Some can be lifted by the priest in confession,” and that is correct. *Some *can in *some *conditions by *some *priests. Others cannot be.
Given the lamentable frequency of voluntary abortion, many diocesan bishops, who possess ordinary power, have given the faculty to remit the penalty of canon 1398 to their priests (see canon 1356 §1). In a particular case, a penitent would have to ask the confessor if he has that faculty. If he does not have it, the confessor would indicate what needs to happen for its remission.
In danger of death, any priest validly and licitly absolves from any kind of censures (c. 976).
Moreover, see canon 1357 §1-3 which concerns the remission of certain censures of excommunication by a confessor, who may “only” be a priest, in the internal sacramental forum, under certain situations.
A person in the sad state of excommunication would be best advised to approach proper Church authority asap for some direction in his or her particular case. The parish priest would normally be the place to start, and could advise the person on what to do, regardless of whether he could remit the penalty or not.