How could vulnerability be a moral virtue?

I have heard the maxim–‘Be vulnerable’–and the laudatory remarks–‘So and so was very vulnerable.’–in creative leadership and entrepreneurial circles too many times to count. Vulnerability is meant to be a moral virtue. How can this be?

We must return to the more familiar connotations of vulnerability. Saying that a baby is vulnerable means that he is susceptible to injury or illness. Vulnerability implies a creature’s proximity to the state of death. Notice that it is the ‘state of death,’ for vulnerability is not, in its most literal sense, an attitude, an outlook, or anything else toward death.

It is not a logical leap to say that entities (systems, states, etc.) can be vulnerable if by this we mean ‘susceptible to external threats, breakdown, collapse, etc.’ Nor is it a logical leap to say that John is fragile or vulnerable just in case John’s mental life is also not robust or resilient: if, that is, John is easily susceptible to falling into the sorts of mental states (melancholy, despair, etc.) when he takes a whole range of events to be devastating or damaging to his flourishing in some strong way or another.

Hence, vulnerability is a ‘location,’ a closeness to the state of death. Being vulnerable may thereby (and often does) evoke fear. These are the senses in which vulnerability as a moral-emotional concept is clear to us. How is it possible (unless by mistake) to think of virtue as a moral virtue? Is it?