For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
Don Fleming
They confess their sins to a priest because they take James 5 v 15 out of context due to the modern versions of the Bible.
James 5:16 >>
Confess your faults one to another, and pray one for another, that ye may be healed. The effectual fervent prayer of a righteous man availeth much.
The AV talks about us confessing our faults to one another, but the word fault in the modern translations has been changed to sins, this makes a huge difference.
There is only one mediator between God and men, the man CHRIST Jesus
No one can forgive our sins but God
Julia Hobert
While I don't have concrete proof that this is true, what I have always been taught was that this was a way to control the people back in the beginning. If the church knew your secrets they can control you. Again, I don't know whether this is true.
James Zuniga
I was born into catholic faith attended a class run by nuns. As I grew up I couldn't understand why I had to confess my sins to a priest. I have nothing against the Catholics, but I needed to know more. I went to a Pentecostal church and learned more, and now I confess my sins to the LORD and feel great knowing that Jesus died for my sins because he loves me. I have many friends who are Catholics and I love them and respect their choice. Amen
Mary Prich
Catholics pray in solitude with God, the virgin Mary, all the anointed saints, their ancestors, and Jesus but also value the opportunity to physically speak with a religious figure, like a priest, who is educated in the minutia of the written word in order to gain clarity on difficult situations that we find ourselves in throughout life. We are part of a community of christians who value the ordained time called confession to reflect on our sins and find ways to live our lives in a more just way with an outside perspective... because when you pray in solitude, no-one speaks back.