There are different definitions of authenticity and one's own definition is not the general rule. Just because someone doesn't convey authenticity the way you expect or want it doesn't mean the person isn't authentic. What many of us don't realize is that judgment prevents us from receiving from the divine Source. The next time you have the urge to verbally or emotionally attack someone, stop for a moment and ask yourself if your reaction is a trigger for some buried trauma.
Why do you feel that this person needs to do it your way and no other way?
Okay, assuming your path is right and the person did everything wrong, why not maybe for a moment, consider approaching the person from a place of love? People carry burdens that we are not always aware of. A cry for help can sometimes manifest itself in many different ways, some of which we are quick to judge as inauthentic behavior. There are no inauthentic or fake souls, so where does inauthentic behavior come from? This is food for thought and would give a deeper insight into the subject of the ruined psyche.
Approaching someone from a place of love can mean: I'm in no position to tell you whether this is the right thing to do or not, but I see you, I hear you and I'm not here to judge.
If life has taught me anything, it is to learn to accept people for who they are and try to see and connect with their higher selves – the self that is not visible to the naked eye. This is the same self they were when they came into this world as a baby and it never changes. That's the self I like to connect with. Not what is presented to me. At times the person may not even be aware of the presence peering behind their eyes, the silenced self which speaks louder than words.
Never communicate with someone when you are angry, spiteful, or judgmental. Why? Because people can read between the lines. That aggression that you might think is so subtle, well hidden is very visible. People can feel the vibrations emanating from your words and actions. They can sense your intention.
We should all learn to always be kind. At times when we've been badly triggered, we should take a moment to reflect, and reconnect with our higher selves before we react.