“Whoever does not judge by what Allah has revealed—those are the unbelievers” (Qur'an 5:44).
Khārijī reasoning appealed to such warnings to declare grave sinners unbelievers. Classical responses distinguish rejection of a divine ruling, deliberate injustice, and failure to comply despite acknowledging the ruling. The verse's setting and relevant interpretations matter when considering its application.
Explicitly denying the rule and violating it while admitting its authority are not identical acts. A sweeping judgment about every person cannot be derived without those distinctions.