The Lord has warned against judging unrighteously (JST Matthew 7:1-2). He has exclusive claim to perceiving—and therefore correctly judging—the heart (1 Samuel 16:7; Alma 18:32), which means we cannot judge a heart righteously. When we attempt to judge a heart, it is based on actions or words or beliefs, which fails to account for a serious component of the mortal experience: deception.
Our words and actions are offspring of our beliefs. We choose our beliefs based on the information we have at a given point. But if any of the information is bad, or our reasoning that builds our beliefs on that information is bad, then we are deceived. Whether the deception is caused by another, or only ourselves, or both jointly, the effect is the same.
Deception is like an infectious and highly contagious disease. It harms directly, but also does splash damage to any others who would turn their disagreement with the deception itself into judgments of its victims; they are fooled into thinking they can judge a heart stricken with deception, thereby contracting it themselves.
When we disagree with the ideas, words and actions of others, we need to account for the possibility that the person actually has a good heart, but has a perspective that is warped by the deceptions under which they suffer. So long as deception is within the world with us, there will be those who have good hearts but are fooled by incorrect ideas (Joseph Smith–Matthew 1:22; 2 Nephi 28:14). They will speak and act in accordance with those false notions until corrected.
We should also consider that they may actually be more correct, and that perhaps it is we who are looking through a lens warped by deception. Or perhaps even both parties are deceived with different deceptions, and the proper truth is yet undiscovered by either party.
All truth can ultimately be circumscribed into one great whole. We hope to eventually understand it in its fullness. Perhaps in that day when we understand all truth with perfect clarity, we can judge one another’s hearts by what we can perceive. Until then, we should recognize that we’ve all changed our minds at some point in time, realizing that something we once believed was actually incorrect. This means that until those epiphanies, we were victims of deception. It is a condition worthy of lamentation and compassion, not mere condemnation.
That said, ideas, words and actions can certainly be separated from people’s hearts, and measured against standards of truth. I believe it is wise and even necessary to do so, for the purpose of learning. But we tend to fail hard at this. We choose instead to take criticisms of those things as criticisms of our hearts and respond defensively and emotionally, rather than looking at them objectively or dispassionately to see what they might teach us. I’d like to explore that more sometime in another post.