Chapter 70 of the Rule is aimed to maintain order in the community. No one is to step out of line and take matters into his own hands. Rather, the concerned person is to take action only in ways that are permitted within the community, or given by the abbot. Anything else can result in the escalation of a problem.
In Benedict’s day there was a permission of physical action, but not to the point of violence. That’s the line which is being drawn in Chapter 70. So, to be safe, Benedict strictly forbids anyone to take physical action against another monk, lest the fine line between physical action and violence be crossed.
Larger than the specific issue being addressed in Chapter 70 is the contaminating effect presumption has. Actions should always be taken in relation to facts. Getting to the bottom of a situation so that facts can surface takes longer than a reactive approach. But it’s only on the basis of facts that a community can be prevented from deteriorating into chaos.
However, when the facts are known, Benedict does allow and even encourages the community to administer actions in keeping with reality and with justice.