That's not true at all.
There are situations where it would be perfectly appropriate to excommunicate a priest, where the priest in question is not trying to set up his own splinter sect of the church.
Maybe I misunderstood fodder then. My point, again, is rather than thinking we need to levy punishments on religions that want to kick out a priest, let's implement a balanced way for them to do it now and save the more complex mechanics for when real schisms come along. No point in getting half-way there now, especially if it's done in a punitive manner.