Actually scripture says once forgiven, the sin is forgotten.. and is (thrown- metaphorically) far as east is from west.. Don't remember where, no matter, forgiven is forgiven..
The only ones obsessed with sin are those that have no idea the power of Jesus Blood and the timeless nature of it.. and the scope of its power.. Usually modern "Pharisees" obsessed with the written law.. missing the Spirit of the law.. Slaves to the letter of the law(rightfully so), and not freed by the Spirit of it by grace and mercy (them personally having neither).. Those are the people that had Jesus murdered by the Romans, and would again.. That today call themselves christians but are really Pharisees.. and they are many..
Sheep are being separated from the goats.. and thats as it should be..
But it should also strike fear in the hearts of many that we are forgiven as we forgive others. People walking around still harboring resentments are effectively asking God to do the same to them.