Only where there is mercy cruelty ends, it ends the evil and violence. Pope Francis is totally in agreement with this line. His pastoral practice is expressed in the fact that he continually speaks to us of God's mercy. It is mercy that moves us towards God, while justice frightens us before him. In my view, this highlights that under the veneer of security himself and his justice today's man hides a deep knowledge of his injuries and his unworthiness before God. He is waiting for the mercy.
It doesn't sound like he isn't on board with Francis and his focus on "mercy". We shall see what he says or doesn't say after this Exhortation is published.
I also don't think Benedict wants to come over as an embittered former Pope who regrets quitting his job nor to be seen as implying that Francis is 100% wrong on everything. He always speaks in a balanced and rational manner, unlike the current incumbent.