How is it more likely that one who has not sinned is better than one who has sinned and repented with sincere repentance?

The preference for one who has not sinned over one who has sinned and repented is because the most obedient of creation to Allah is he who has not sinned. The one who is quick to obey is superior to the one who repents later. The ultimate argument is that repentance only erases sin, while the obedient person is in continuous pursuit and acquisition [of good deeds]. Allah dislikes the disobedient while He is pleased with the obedient. Sin is like poison, and repentance is its antidote, while obedience is continuous health. As for preferring the repentant, there is another opinion, strengthened by Allah's love for repentance and His joy at the repentance of the repentant, and what repentance entails of humility and brokenness, and the transformation of bad deeds into good deeds. Sheikh al-Islam preferred that this varies according to the state of the repentant after their repentance, their diligence, their resolve, their caution, and their readiness. If these are greater than what they had before the sin, then they are better than one who has not sinned.