The psalmist realizes, as we all should, that our sins are the source of all of our troubles. And that, if our sins are forgiven and removed, then logic dictates that our troubles likewise will be removed.
And therefore our first petition, to gain access to our spiritual life, is by means of our request for the pardoning of our sins, thus paving the way for God to remove our problems.
And this first petition, is what we call confession.
If we confess our sins, He is faithful and just, to forgive us of all our sins, and cleanse us from all unrighteousness. That is the method and means of restoring ourselves into fellowship with God, and into the sphere of a functioning spiritual life.
It is the individual who does not have a relationship with God, who is the fool.
Having a relationship with God is the simplest thing in the world. And not knowing it, and especially ignoring it, is the method and function of the fool.
A fool lives in evil. Evil is everything outside of the realm of God and truth and the spiritual life.
Evil is a reproach. And a fool who lives in evil, by default is a reproach to truth and everything in life.
Therefore, confessing one sins, resulting in the removal of those sins, in effect removes the reproach from ones life.