Is the innovation of the Rafidah a cause of disbelief or a cause of open sinfulness?

Question:
Some people say that among the Rafidah, some have an innovation that is a cause of disbelief, and some have an innovation that is a cause of open sinfulness. Is this a correct classification?

Answer:
The Rafidah are divided into sections. Al-Shahrastani mentioned that they are twenty-two sections. The Rafidah are numerous sections, the Shi'ah, but the Imami Rafidah exaggerate regarding 'Ali and the People of the House, and they say: He knows the unseen, and they worship them. These are disbelievers.
But some of the Shi'ah are less than that: those who prefer 'Ali over 'Uthman, or over al-Siddiq and 'Umar. These are innovators; they are not declared disbelievers for this. Likewise, among them are the Zaydiyyah, one of the sections and sects of the Shi'ah: they prefer 'Ali over 'Uthman.
Q: And who declares them disbelievers, does he declare them disbelievers by their specific identity or by their type?
A: Whoever is known by his specific identity to claim knowledge of the unseen, or to exaggerate regarding the Household of the Prophet; he is a disbeliever by his specific identity. One of the type of those who worshipped 'Ali or others is a disbeliever, or one who claimed that he knows the unseen is a disbeliever.