I don't have to explain anything. It is what it is. Can we explain why the Universe exists (as opposed to how), or why the Sun isn't blue, or why we don't see in 1-dimension instead of 3? The patterns of reality constitute what Is, and what Is cannot be changed. So what Is pertaining to Good vs. Evil...?
1. Truth is Survival. Therefore, Truth is seen as Good.
2. "truth" is the word used to describe knowledge that is correctly aligned with reality. Truth does not equal "truth".
3. Anti-Truth is Anti-Survival. Therefore, Anti-Truth is seen as Evil.
I explained a bit of this in my short essay 'Modes of Truth and Survival'.
I'm tired, I'll finish this later...