I preach sermons quite often (as a layperson), and while my church (Methodist) many times seems reluctant to call sin by its name, I'm pretty sure that most sinners don't need to be told they are sinners. They might need to be called on their rationalizations, but God has made himself known; we all know when we're doing wrong.
Don't take this wrongly, but Jesus saved his outrage for the self-righteous, and the moneychangers (both of whom put obstacles on people getting right with God). The sinners he interacted with knew they were sinners. His attitude toward them melted their hearts, and they turned to Him.
This is not to say he pretended sin didn't exist. But he treated it as a given and went forward from there. The people followed Him.