What we've missed is the whole point. Vulnerability and realness in relationships implies that there is a risk. The risk is getting hurt. Otherwise there would be nothing vulnerable about being vulnerable.
Jesus knows this. He also knows that it is worth the risk. What is gained when there really is a connection between God's kids far outweighs the temporal hurt and confusion that comes through betrayal. Even when betrayal is the norm and connection is the exception.
That's why He tells us to "love one another as yourself" and to "share everything in common" and to "confess to one another" and to "defend each other." That's why He did all these things Himself, with a bunch of guys He knew would betray Him.
Now, the serious question is this:
Do you trust Him enough to be vulnerable with other believers - over and over again - knowing that the outcome will most often hurt?
I'll be honest, that is a hard question for me to answer. But, He's never failed me before.