Why do they not follow Scripture and throw him out until he repents??
This is as serious as it gets. Durbin’s out of Communion. What do you want, defenestration?
If you are asking why Durbin hasn't been excommunicated, that isn't what you think it is. Having been baptized a Roman Catholic there is nothing Durbin can do to be expelled from the church. Baptism is irreversible.
Excommunication means that a person is banned from receiving Communion. It's a formal declaration that is pretty much a last resort. By banning Durbin from receiving communion, Bishop Paprocki is basically saying to Durbin, "Last chance." Formal excommunication would be the next step unless Durbin repents.