The faults we are dealing with here are betrayals of community life. They involve drawing benefits from a community while behaving in such a way that threatens the community's health. As such, St. Benedict fixes the consequences for these faults squarely at the heart of Benedictine community life, at the table and in prayer.
The connotations of the word "excommunication" in our current understanding are distracting, if we seek to understand the spirit of our Father Benedict's instructions. This is not excommunication in the idiom of banishment to eternal damnation. This is not a bishop cutting off a Roman Catholic nun from her church for political reasons. This word is used here to indicate a far more literal dynamic, that of being "excluded from the common" aspects of life in the monastery. And, depending on the seriousness of the fault as judged by the religious Superior, this excommunication is applied in degrees toward a two-fold end: the preservation of community health and the restoration of the wayward member.
This is the original "natural and logical consequence" method of discipline put in place by a parent who loves us (RB: Prologue).