psalm103: is talking about sin opressive?

In my opinion, psychologists try to elevate the self-steem of their patients. Talking about sin is oppressive. Some pastors go in this direction too. 

In Psalm 103, we read:

8 Yahweh is compassionate, merciful, patient,

    and always ready to forgive.

9 He will not always accuse us of wrong

    or be angry with us forever.

If sin can't be treated or forgiven, then talking about sin is very oppressive. However, the Lord will not always accuse us of wrong. He is merciful and patient. 

3 As a father has compassion for his children,

    so Yahweh has compassion for those who fear him.

He understands us:

14 He certainly knows what we are made of.

    He bears in mind that we are dust.

When we accept who we are, and we understand what the Lord has done to us, we say:

22 Praise Yahweh, all his creatures

    in all the places of his empire.

    Praise Yahweh, my soul!