Hi I think they cheered him not condoning of his sin but in support of where he has gone on since then. David committed adultery and had Uriah killed to cover up his sin and God called David out who openly repented and psalm 51 is a powerful song of repentance.
o the Chief Musician. A Psalm of David when Nathan the prophet went to him, after he had gone in to Bathsheba.
1 Have mercy upon me, O God,
According to Your lovingkindness;
According to the multitude of Your tender mercies,
Blot out my transgressions.
2 Wash me thoroughly from my iniquity,
And cleanse me from my sin.
3 For I acknowledge my transgressions,
And my sin is always before me.
4 Against You, You only, have I sinned,
And done this evil in Your sight—
That You may be found just when You speak,[fn]
And blameless when You judge.
5 Behold, I was brought forth in iniquity,
And in sin my mother conceived me.
6 Behold, You desire truth in the inward parts,
And in the hidden part You will make me to know wisdom.
7 Purge me with hyssop, and I shall be clean;
Wash me, and I shall be whiter than snow.
8 Make me hear joy and gladness,
That the bones You have broken may rejoice.
9 Hide Your face from my sins,
And blot out all my iniquities.
10 Create in me a clean heart, O God,
And renew a steadfast spirit within me.
11 Do not cast me away from Your presence,
And do not take Your Holy Spirit from me.
12 Restore to me the joy of Your salvation,
And uphold me by Your generous Spirit.
13 Then I will teach transgressors Your ways,
And sinners shall be converted to You.
14 Deliver me from the guilt of bloodshed, O God,
The God of my salvation,
And my tongue shall sing aloud of Your righteousness.
15 O Lord, open my lips,
And my mouth shall show forth Your praise.
16 For You do not desire sacrifice, or else I would give it;
You do not delight in burnt offering.
17 The sacrifices of God are a broken spirit,
A broken and a contrite heart—
These, O God, You will not despise.
18 Do good in Your good pleasure to Zion;
Build the walls of Jerusalem.
19 Then You shall be pleased with the sacrifices of righteousness,
With burnt offering and whole burnt offering;
Then they shall offer bulls on Your altar.
David afterwards was called a man after Gods own heart.
This man back then was an adult but her being 17 and him being 22 is borderline on age difference. He had to have courage to admit what he did openly and apologize for it. Many other people would have denied anything as at this point it is a he said she said sort of thing. He has obviously moved past this and she should too. Her bringing it up now seems a bit vengeful as the guy he is now is not the same guy from 20 years ago. I do not want to marginalize the past incident and dismiss it but we should always forgive others as Christ has also forgiven us. If she had this attitude she might have addressed the situation privately rather than publicly.
