Whether Karl Keating believes that the Pope should respond to the Dubia is irrelevant. That is his opinion and does not ipso facto imply that he believes that Amoris Laetitia contains heresies. Clarification from the Pope is a prudent idea - which includes answering the Dubia, but nothing here concerns dogma so it is not important and does not place Catholic Answers at odds with the Church.
The Church still teaches that adultery is a grave sin. This comes straight from God in the Ten Commandments (divine law). But the Church also knows that there are factors that may come into play in specific circumstances, and not everything is so “black-and-white” in regard to sin. Only mortal sin can condemn one to hell, not venial sins. For a sin to be mortal, it must be a grave matter; one must have full knowledge that the sin is a grave matter; and they must give full consent in spite of the fact that they know what they are going to do is a grave sin.
So it is perfectly possible that a Catholic who divorced and remarried without an annulment could be doing all this without committing a mortal sin! And since only mortal sin bars one from communion, it is possible for the person to receive communion without committing a sacrilege.
What Pope Francis wants is to allow Catholics in these irregular marriages to discern with a confessor to determine whether their actions constituted a mortal sin given their own personal circumstances. While doing this, he changed an ecclesiastical law, but never denied dogma. He never claimed that adultery is not a mortal sin when the conditions for a mortal sin are met.
However, the practice used to be to never allow divorced and remarried Catholics to receive communion, no matter the circumstances. The Pope changed this but did not compromise dogma. He changed an ecclesiastical law, which he has the authority to do, but NOT a divine law (which no one has the authority to change).
This “pastoral judgement” is not on whether adultery is a sin, but on whether those who are divorced and remarried but still free from mortal sin due to lack of sufficient knowledge or full consent should be admitted to communion. The Pope said yes, but many Catholics disagree. And since these Catholics only disagree with a practice, this is acceptable.
In my personal opinion, I think this was an imprudent move. While I get that he wants to “show mercy” to divorced and remarried Catholics who are free from mortal sin, it increases the possibility of public scandal. If someone has privately discerned with a confessor that they can receive communion, it cannot be assumed that everyone else would know that. This would make it seem that the Church is allowing adultery by admitting these people to communion.
It’s complicated because while the Church wants to avoid scandal, she also doesn’t want to refuse communion to people to are not in a state of mortal sin, but perceived to be by others who do not understand their circumstances. Whether one agrees or disagrees with the Pope’s decision to modify ecclesiastical law, however, does not make them either orthodox or heretical.