To imply that due to “forms of conditioning and mitigating factors”, personal conscience may trump Divine Law must be material heresy, at the very least. The insinuation is blindingly clear (despite the sly wording within which it is couched).
“Because of forms of conditioning and mitigating factors, it is possible that in an objective situation of sin – which may not be subjectively culpable, or fully such – a person can be living in God’s grace, can love and can also grow in the life of grace and charity, while receiving the Church’s help to this end. [Footnote 351 here]
351 In certain cases, this can include the help of the sacraments. Hence, “I want to remind priests that the confessional must not be a torture chamber, but rather an encounter with the Lord’s mercy” (Apostolic Exhortation Evangelii Gaudium [24 November 2013], 44: AAS 105 [2013], 1038). I would also point out that the Eucharist “is not a prize for the perfect, but a powerful medicine and nourishment for the weak” (ibid., 47: 1039).”
Mortal sin requires one exterior, and two interior factors. The one exterior factor is "grave matter" something that is in grave opposition to God's Law. The two interior factors are sufficient knowledge, and the consent of the will.
Note it's not "perfect" knowledge or "perfect" consent, which are conditions available perhaps to angels, but not to us. The ordinary control that a normal person has over his or her own thoughts and actions, is sufficient for imputing the guilt of a mortal sin.
I remember when "Amnesia" was a theme of a lot of TV dramas. The character would get a good knock on the head, and then get baffled about his real identity and --- this was key to the drama -- forget who he was married to! ("Whoa! Who's my wife? Could it be you, pretty lady?") This led to all kinds of steamy situations until he finally got his brains unscrambled and figured out what was going on.
This person would arguably lack the cognitive capacity and interior freedom for a mortal sin of adultery.
Anybody else? Look, if you're past your 18th birthday and you've got sufficient intellect/maturity to assume monthly payments on a car or a cell phone, your mind and will are intact. You are NOT off the hook.
That's how I see it, anyway. God is the judge of interior states, but objectively, if you've divorced and remarried outside the Church, you didn't do so "inadvertently". You know the Church says --- and Jesus says, five times in the Gospels --- that that ain't right.
At least, that's how I see it.