Ibn Taymiyyah...
Ibn Taymiyyah, the Shaykhul Islam of the Wahabis, writes And merely abusing someone other than the Prophets does not necessarily make the abuser Kafir; because some of those who were in the time of the Prophet (i.e companions) used to abuse one another and none of them was declared kafir because of this (practice); and (also) because it is not Wajib to have faith, particularly in any of the companions; therefore abusing any of them does not detract from the faith in Allah and His books and His messengers and the Last day.
(5) The name of Mulla Ali Qari requires no introduction to the Sunnis, and he writes in his work of Sharah Fiqh al Akbar that To abuse Abu Bakr and Umar is not Kufr, as Abush Shakur as Salimi has correctly proved in his book, at Tamhid. And it is because the basis of this claim (a claim that reviling the Shaykhan is kufr) is not proven, nor is its meaning confirmed.
It is so because certainly abusing a Muslim is a sin as is proved by a confirmed hadith, and therefore the Shaykhan (Abu Bakr and Umar) will be equal to the other (Muslims) in this rule; and also if we suppose that someone murdered the Shaykhan, and even the two sons in law (Ali and Usman), all of them together, even then according to Ahlussunnah wa al- Jamah, he will not go out of Islam (i.e will not become kafir).
(6) Interesting note: The above quote was taken from three editions, printed in India and Turkey. Now a new edition has been printed by Darul Lutubil Ilmiyah, Beirut in 1404/1984, which claims to be the first edition, and from which four pages (including the above text) have been omitted. The deleted portion contains the declaration that … those who believe that Allah has a body are definitely kafir according to the Ijma without any difference of opinions.
Do I need to comment on the Wahhabi scholarship? Another person mentioned: Why is it that you want Sunnis to accept a selected number of traditions from the Sunni sources which refute the integrity of people like Abu Bakr, and Umar Ibn al-Khattab? This point really irks me. I am sorry it irks you! It is not completely correct, however. We have nothing against the persons of Abu-Bakr, Umar and Ashia.
We are looking at history in retrospect and evaluating their actions – which should not be considered a sin. After all, they were human beings who were capable of making mistakes. Why not learn from their mistakes – particularly if done in a sensitive way?