Is it permissible for ordinary people to label as a kaafir one who reviles Islam, without referring to the scholars concerning that?

Is it permissible for ordinary people, if they hear someone reviling
Allah or Islam or the Messenger (blessings and peace of Allah be upon
him) to label him akaafir without referring to the scholars?.
Praise be to Allaah.
Firstly:
There is no doubt that reviling Allah, may He be exalted – Allah
forbid – or reviling His Messengeror His religion – Allah forbid –
comes under the heading of disbelief in Allah the Almighty. The one
who does that has committed major kufr that puts one beyond the pale
of Islam. If he dies in that state without having repented from it,
then he will be one of the people of Hell who will abide therein for
all eternity.
Shaykh Ibn Baaz (may Allah have mercy on him) said:
The scholars are unanimously and definitively agreed that if a Muslim
reviles Islam, or criticises it, or he reviles the Messenger
(blessings and peace of Allah be upon him), or criticises or mocks
him, then he is an apostate and a kaafir and it is permissible to
sentence him to death and seize his wealth.
End quote from Fataawa Noor 'ala ad-Darb by Ibn Baaz, p. 139
Shaykh Ibn Jibreen (may Allah have mercy on him) was asked:
What is the ruling on one who reviles Allah and His Religion? What
isthe expiation for that? Please note that the manconcerned is
married; does his wife become haraam for him or is she divorced?
He replied:
There is no doubt that this is apostasy from Islam and disbelief in
Allah for which the person who does it deserves to be sentenced to
death unless he repents; his wife is divorced from him and his ties of
kinship with his relativesare severed, so he does not inherit from
them and they do not inherit from him. But if he repents, regrets it,
prays for forgiveness and acknowledges his mistake, Allah will
accepthis repentance and he can take his wife back if her 'iddah has
not ended; if it has ended then it is up to her, and it is not
permissible for him to take her back except with her consent.
End quote from Fataawa Islamiyyah, 3/533
Secondly:
If a person hears someone clearly reviling Allah, or shar'i proof is
established to that effect, then there is nothing wrong with
himbelieving that this person is a kaafir. This is the most abhorrent
and serious kind of reviling, and no one does that except one who has
gone far astray and has no respect for Allah, mayHe be glorified and
exalted, or one who has lost his mind and does not know what he is
saying.
This kind of reviling is not one of the obscure issues that need a
ruling from the scholars or need to be subjected to examination;
rather it is something very clear and obvious that can be recognised
by ignorant and knowledgeable alike, and old and youngwill be
disgusted by it.
But at the same time it isessential to bear in mindthe shar'i purpose
behind denouncing that and regarding it as repugnant, which is to
remove and ward off that evil and to strive to make the one who said
it repent and come back to his Lord, even if he has apostatised and
gone beyond the pale ofIslam. Asking the apostate to repent is
something that is well known and well established. So efforts should
be made to exhort him in a manner that is appropriate to hissituation,
explaining the abhorrent nature of what he has done and todiscuss with
him the shar'i way that is appropriate to his situation.
The scholars of the Standing Committee said:
Reviling Islam – Allah forbid – is kufr according to the texts and
scholarly consensus. Allah, may He be exalted,said (interpretation of
the meaning):
"Was it at Allah, and His Ayat (proofs, evidences, verses, lessons,
signs, revelations, etc.) and His Messenger (SAW) that you were
mocking?
Make no excuse; you have disbelieved after you had believed"
[at-Tawbah 9:65].
And there are other similar texts.
It is essential to advise him and denounce him for that; if he
responds, praise be to Allah, otherwise it is not permissible to
initiate the greeting of salaam with one who has reviled Islam, or to
return his greeting if he initiates the greeting; it is not
permissible to accept his invitation andhe must be shunned completely
until he repents or until the ruling of Allah, which is to be
sentenced to death, is carried out on him by the authorities, because
the Prophet (blessings and peace of Allah be upon him) said: "Whoever
changes his religion, execute him." Narrated by al-Bukhaari in his
Saheeh, 3017.
End quote from Fataawa al-Lajnah ad-Daa'imah, 2/12
Shaykh Ibn 'Uthaymeen (may Allah have mercy on him) said:
If a person repents from any sin, even if that was reviling Islam, his
repentance will be accepted, if he fulfils the conditions that we have
mentioned. However it should be noted that a word may constitute kufr
or apostasy, but the one who utters it does not (necessarily) becomea
kaafir thereby, because of the presence of some factor that prevents
him being labelled as a kaafir. In the case of this man whosaid that
he reviled Islamin a moment of anger, we say to him: If your anger was
so severe thatyou did not know what you were saying, and you did not
know whether you were in thesky or on the ground, and you said
something without thinking and not knowing what you were saying, there
is no ruling that is applicable to these words and you are not to be
labelled an apostate, because this is something that was said
involuntarily and without thinking, and if anything is said
involuntarily and without meaning to, Allah, may He be glorified and
exalted, will not bring one to account for it. Allah, mayHe be
exalted, says concerning vows (interpretation of the meaning): "Allah
will notcall you to account for that which is unintentional in your
oaths, but He will call you to account for that which your hearts have
earned" [al-Baqarah 2:225].