There was sexual immorality in the church at Corinth and it needed to be dealt with. Mourning and excommunication were the prescription, restoration and seeking the forgiving and transforming grace of Christ the anticipated outcome.
This is not a Corinthian problem. Our sexualized culture has had a significant impact on the church. Pornography, for example, is common in our churches. We ought to mourn, we ought to deal with sin. May this text be a call to get right with God, to seek him for his love and mercy.