Spot on, although I will suggest that there is an inherently protective effect to closing ourselves off. The problem is, what we are protecting ourselves from is largely the product of our internal storytelling.
In my past job I needed to attend a lot of conferences and conventions. I am not a fan of large crowds, and I usually would “ armor” myself in some way in these situations. Then, I attended a large conference with the intention of being very open. The results were staggering! People were drawn to me in ways I had not previously experienced at these events. It was an eye opener. It also was not easily replicated, because it still was not a habit. It turns out that the courage to be open is not a one-off event. But then, courage comes from the Latin word for heart. So courage and open heartedness go hand in hand.