Choosing mercy over judgement is something you have to practice to master. How many times have we figuratively pointed our finger at someone and say "He's going to hell!" or "Don't associate with that person, he's gay!" Choosing mercy or judgment allows us to focus on the good things about someone. It's not that we are overlooking that person's sin or not giving it a second thought but it's not our job to judge when there is a much higher power already doing that for us. When Jesus died on the cross for our sins, those sins included ALL sins, not just the ones we want to pick and choose. We have to trust in the Lord that he's going to address those sins at the proper time for that individual. In the mean time we can focus on the good of ALL people as much we can humanly can.