What is the ruling on initiating the greeting of "peace" (Salam) to someone who commits a sin, such as a man who shaves his beard, or lowers his garment below the ankles, or smokes?

The right of a Muslim upon another Muslim includes greeting him with peace (salam), and this right is not nullified by the commission of sins, especially minor ones, or if the sinner is concealing his repentance. As for shunning a sinner, it is legislated if he commits major sins and has not repented from them, and if shunning achieves a benefit such as disciplining him and protecting society, especially if he is openly committing the sin. However, if shunning does not achieve a benefit or worsens the situation, then it is better to greet him with peace and win over his heart. Shunning is legislated and required if it serves as a remedy for the sinner and leads to his rectitude. The rule is that فسوق (transgression/immorality) does not expel a person from faith, and shunning is permissible if there is a benefit for the transgressor; otherwise, do not shun him, but rather greet him and advise him. Avoiding shunning, showing forbearance, and seeking reconciliation are emphasized when the Sunnah and its adherents are weak. Shunning can be a form of ta'zeer (disciplinary punishment) or punishment, and for ta'zeer, the ability to implement it and consideration of the predominant religious benefit are prerequisites.

As for examples like isbal (letting one's garment hang below the ankles), smoking, and shaving the beard, their perpetrators should not be shunned if they are ignorant of the ruling, or are following the opinion of a mufti, or are compelled, or have an interpretation, because an excuse is applicable in their case.