So I think there are a few subtle things packed into the Pope's statement.
First: A lot of Catholic morality derives from the postulate that man was specially made by God and "in God's image" which gives man an inherent, unique-among-all-creation dignity. Because of this, the church is very sensitive to anything which diminishes the "specialness" of man, as they fear it will undermine people's reasons for treating each other with respect. Its part of the reason why they were initially anti-heliocentrism (man wasn't at the center of the universe) and anti-evolution (man wasn't specially created) before coming around due to overwhelming evidence. The pope is concerned that AI falls into this category of "challenge to human dignity" because it gives the sense that man's cognitive abilities are not unique.
Second: A lot of Catholic theology regarding the soul is driven by god-of-the-gaps style reasoning. Indeed, if you look back at Thomas Aquinas's writings on the soul with a modern bio understanding, its painfully clear that his conception of the "soul" is just his attempt at understanding metabolism without any solid physics or chemistry. Obviously no one today says that the soul is in charge of the "locomotion" of living things, but up until very recently the one last bastion of unexplained behavior where the religious could justify their belief in the soul was the intellect. AI is a direct assault on this final motte, as it is concrete evidence that many of the "intellectual" outputs of the soul could, at least in principle, have a naturalistic explanation. (There was plenty of evidence of the intellect being fully naturalistic prior to AI, but it wasn't the kind of irrefutable "here's a fully natural thing that does the thing you said natural things couldn't do" evidence).
First: A lot of Catholic morality derives from the postulate that man was specially made by God and "in God's image" which gives man an inherent, unique-among-all-creation dignity. Because of this, the church is very sensitive to anything which diminishes the "specialness" of man, as they fear it will undermine people's reasons for treating each other with respect. Its part of the reason why they were initially anti-heliocentrism (man wasn't at the center of the universe) and anti-evolution (man wasn't specially created) before coming around due to overwhelming evidence. The pope is concerned that AI falls into this category of "challenge to human dignity" because it gives the sense that man's cognitive abilities are not unique.
Second: A lot of Catholic theology regarding the soul is driven by god-of-the-gaps style reasoning. Indeed, if you look back at Thomas Aquinas's writings on the soul with a modern bio understanding, its painfully clear that his conception of the "soul" is just his attempt at understanding metabolism without any solid physics or chemistry. Obviously no one today says that the soul is in charge of the "locomotion" of living things, but up until very recently the one last bastion of unexplained behavior where the religious could justify their belief in the soul was the intellect. AI is a direct assault on this final motte, as it is concrete evidence that many of the "intellectual" outputs of the soul could, at least in principle, have a naturalistic explanation. (There was plenty of evidence of the intellect being fully naturalistic prior to AI, but it wasn't the kind of irrefutable "here's a fully natural thing that does the thing you said natural things couldn't do" evidence).
Aquinas: https://www.newadvent.org/summa/1078.htm