Those who think the Pope’s emphasis on mercy supports laxity—whether critics or people who wrongly hope for change of teaching—misunderstand what mercy is. I find that Bishop Robert Barron has a good response, rejecting that view:
Many receive the message of divine mercy as tantamount to a denial of the reality of sin, as though sin no longer matters. But just the contrary is the case. To speak of mercy is to be intensely aware of sin and its peculiar form of destructiveness.
Barron, Robert (2016-03-31). Vibrant Paradoxes: The Both/And of Catholicism (Kindle Locations 199-201). Word on Fire. Kindle Edition.
His response is a good one. Jesus showed mercy to sinners. He did not tell the that their sins did not matter. The Pope doesn’t tell people that their sins do not matter either. What the Pope does say is it is not enough to tell people what is wrong. We also have to help them get back to what is right.