As for declaring someone a disbeliever on account of a sin or a belief consistent with the Sunnah, this is the doctrine of the Kharijites. Declaring someone a disbeliever on account of a belief consistent with the Sunnah is the doctrine of the Rāfidah, the Muʿtazilah, and many others. As for declaring someone a disbeliever on account of an innovated belief, I have explained this elsewhere.

Even short of declaring someone a disbeliever, some of these interpretations may lead to impermissible hatred, censure, and punishment—which constitute transgression—or to withholding love, supplication, and kindness—which constitutes neglect. All of this amounts to violating the rights of Allah Most High or those of His creatures, as I have explained elsewhere.

For this reason, Ahmad ibn Hanbal said to one of his companions:
“Most of people’s errors arise from interpretation and analogical reasoning.”