Is it permissible for common folk to declare someone who insults Allah, religion, or the Prophet, peace be upon him, an infidel without referring to scholars?

Cursing Allah, His Messenger, or the religion is a major act of disbelief (kufr akbar) that expels one from the fold of Islam, by scholarly consensus. Whoever dies upon it without repenting will be among the people of Hellfire. Anyone who curses the religion becomes an apostate and is to be executed unless he repents, and his wife is divorced. It is permissible to believe in the disbelief of one who explicitly curses Allah, and this is not among hidden matters. The one who curses should be advised and called to repentance. If he responds, then all praise is due to Allah. Otherwise, one should not greet him with salam, nor accept his invitation, and he should be boycotted until he repents or the judgment of Allah is carried out upon him. The repentance of one who cursed the religion is accepted if it fulfills the conditions. However, the disbelief of one who curses the religion might not be ruled in the case of extreme anger that deprives him of his consciousness, because his words at that time are without will or intention.