"Confession" is a strange word. It has two distinct meanings:
1) An admission of personal guilt for some evil act.
2) A humble, even self-effacing, but resolute and implacable declaration of belief. Often used in a religious setting, i.e. "to confess one's faith in God".
The second definition borrows the feeling from the first one - the deflated spirit of the guilty admitting his guilt, his shamefulness in the eyes of the world. But the two definitions have very different substance. In the second meaning, personal humility cloaks immense pride in some other thing. It is an irony contained in a single word.
English is a tricky language.