It's a fault of human nature to seek for ways around the teachings of Jesus, especially in the arena of forgiving those who wrong us. Outright forgiving someone who's wronged us is difficult, I agree, especially when there's no sign of secured repentance. It takes some fortitude to follow through with that. When we choose to take the matter outside the Church, in effect seeking revenge, we make the original sin worse.
Paul was only backing up the spirit of Jesus' teaching. If it is ignored, then great damage to the Church and to individual members lies at the door.
Being critters that will one day judge angels and the world, we ought to know it is within our collective power to judge relatively insignificant matters without taking it outside the Church. Whatever happened to prayer for wisdom?
If the "least esteemed" Christian, a person in Christ that never gets nominated for election to Usher, or Deacon on the Board, or asked to teach Sunday School, never recommended to be on a single committee, is a Christian, having the Holy Spirit in them, can't be trusted to simply hear out a simple, non-corporate complicated dispute, then that church has a serious problem. Do we discriminate, saying to the left little toe "I could do without you?". I can testify that every least part of my body is important, as when that little toe got a hard corn between it and the next toe, my life changed a while. It didn't matter how "important" or healthy the other parts were.
Any dispute between just two Christians is subject to discovery of wrongs and ways to weigh wrongs by even brethren that might not have a high school diploma, but have experienced "life", and know right from wrong, hearing the Bible taught many years. I've watched it happen too many times to count, little old elder grandmothers sitting in on a young couple's dispute, instantly knowing the problems and one or more solutions. There really is nothing new under the sun. Living out such decisions over many decades qualifies people in Christ to present answers pleasing to the Lord, those answers seasoned by the Word and prayer of faith, if not but a single passage of scripture involved.