Lets look at the word sinner in our Strong's as it is used here. The Pharisees were the religious leaders of that time. They were not appointed by our Heavenly Father, but by the Romans. But when Jesus heard that, he said unto them, They that be whole need not a physician, but they that are sick. You see many religious leaders of that time were stuck in the traditions of man.
Lets go to the Minor Prophets, to the book of Hosea.
Here our Father is saying to two of the of the twelve tribes. Your devotion to Me is like a cloud in the morning. All of you have seen clouds in the morning, when the heat of the sun hits them they evaporate into nothing. Our Father desires kindness not sacrifices also He wants you to have the knowledge of Him more than He wants burnt offerings. Lets turn to another book in the Minor Prophets, to the book of Micah.