We must recognize that every person who believes in Allah and in His Messenger cannot be devoid of some inborn good, however evil his practice may be. Involvement in major transgressions does not uproot a person's iman unless the transgressor deliberately defies Allah and scorns His commands. Here, as elsewhere, we have to heed the Sunnah of the Prophet, peace be upon him, who used to treat wrongdoers as a physician would treat a patient, not as a policeman would treat a criminal. He was very kind to them and always listened to their problems.
During the lifetime of the Prophet there was an alcoholic who was repeatedly brought to the Prophet and was repeatedly punished, yet still persisted. One day when he was brought again on the same charge and was lashed, a man from among the people said: "May Allah curse him! How frequently has he been brought [to the Prophet to be punished]?" The Prophet said: "Do not curse him. By Allah I know he loves Allah and His Messenger." It is also reported that the Prophet said: "Do not assist Satan against your brother." The Prophet prevented them from cursing him because their action could create discord and ill feeling between the man and his fellow Muslim brothers - his transgression should not sever the bond of brotherhood between him and other Muslims.
Deep contemplation of the above example and incident amply demonstrates the Prophet's insight into the inherent element of goodness in man. We need, more than ever before, to study and follow the exemplary pattern that the Prophet has set for us. Those extremists who indiscriminately accuse whoever makes a mistake of kufr or shirk must understand that they have to change their strategy and learn that a great deal of the corruption and perversion they abhor results mainly from ignorance of Islam, bad company, or forgetfulness. The solution is to help people overcome and defeat all these problems. To be harsh, to accuse others of kufr, and to find fault with whatever they do only serves to alienate and estrange them. A wise man once said: "Rather than cursing darkness, try to light a candle for the road."
Islam: The Way of Revival,"The Ethics of Daw'wah and Dialogue" - Yusuf al Qaradawi, pp. 224, 225