Greetings in that Divine and Most Precious Name of Our Lord and Savior Jesus CHrist!
Error is subtle and seductive. If it weren't, no one would follow it.
I agree, theologically speaking, error is human. This is not in the Catholic sense of a spiritual corruption to human nature by essence from Sin. No, our nature is in tact as God created us, it has the same potentiality for Grace and Sin that it always had. By error is human I mean in the sense of manifesting our own individual, selfish, free-will as compared to embracing the outside Will of God. The be human is to have free-will, this is the core of our existence, even at a subtly spiritual level. God however, does not FORCE us to follow His Will, through love and embrace we are to learn to adjust our own will towards His own. However, as demonstrated by our own human relationships and interactions with each other, getting two human beings on the same page at any level is generally impossible. Even when we work together, it is rarely for the same reasons. Even if we agree, there are always shades of grey to debate. We are more so convinced to syncretically blend our wills, but not necessarily having fully changed our own wills. This is the error of not following God's Will. God's Will is the Church, and our will is ourselves. It is therefore naturally easier to follow our own will and fall into heresies because these conform not to Divine Will, but pander and posture towards the human ego. We are inflated and puffed up by heresies, we feel a false sense of empowerment because we are manifesting our own will. Even in the Church, folks make this same error.
We don't fast, we don't celebrate the Divine Liturgy, we weren't Baptized out of our own sense of free-will, rather we yield to God in these matters precisely to change our will and learn to put our faith and trust in His. Heresies do the opposite, they are human errors which then to humans naturally don't feel like errors at all, they feel like empowering truths because they empower the very selfish core of our experience, the ego and the inward self. God is challenging us to embrace Him and abandon ourselves to His Will, hence the prayer, "Thy Will be done." Heresies are the flip side to that prayer, manifestations of, "Whatever the consequences our own wills be done."