It would be this question "Is the law not also a part of mercy"?
From his closing comments to the synod, in which he was rather harsh with those who follow the law "The Church’s first duty is not to hand down condemnations or anathemas, but to proclaim God’s mercy, to call to conversion, and to lead all men and women to salvation in the Lord (cf. Jn 12:44-50)."- Pope Francis conclusion to the 2015 synod
I see repentance as necessary for mercy. Justice, repentance, and Mercy, the human trinity.
The way this is shown is in the eternal call to conversion- a person who doesn't know his sin is a sin can't convert. The reason for the condemnations and anathemas is precisely the call to conversion.
If you are looking for more of my evolving thoughts on this subject, use the labels to find other related posts.