One of the nuns' concerns was Butker's assertion that being a homemaker is the highest calling for a woman. This statement goes against the true Catholic teaching that a calling to the priesthood or religious life is the highest calling: Canon X Session 24 of the Council of Trent—If any one saith, that the marriage state is to be placed above the state of virginity, or of celibacy, and that it is not better and more blessed to remain in virginity, or in celibacy, than to be united in matrimony: let him be anathema.

So in fact, one of the the nuns' concerns is based entirely in Catholic dogma which Butker contradicted.