Should he shun those who slander and mock the scholars of Ahl as-Sunnah?
Question

                In my town there is a asharee daiya who said that his scholars have said that the likes of bin baz and uthaymin rahimahumullah are like chickens they have wings but they can fly. i believe that they also believe ahlul athar are mujasima. how should i deal with such people, should we initiate salam. is it permissible to not co operate with them, can we reject an invitation from them? also what is the dua one of the sahaba would say when completing the quran. also what is worse masturbation or watching pornography? is oral sex haram? there is no daleel against it but shaykh Al albani rahimahullah said it is bad right?.
Praise be to Allah.Firstly: 
With regard to 
    reviling, slandering, mocking and making fun of (scholars), that is 
    something that anyone could do. The most skilled of people in reviling and 
    mocking are those who are furthest removed from religious commitment, good 
    attitude and dignity. This is something that should not be done by one who 
    understands religion; rather he should avoid it. The Prophet (blessings and 
    peace of Allah be upon him) said: “Reviling a Muslim is evildoing and 
    fighting him is kufr.” Agreed upon. 
Allah, may He 
    be exalted, described the criminals and disbelievers in His Book, and listed 
    as one of their attributes their mockery of the believers. Allah says 
    (interpretation of the meaning):
“Verily! 
    (During the worldly life) those who committed crimes used to laugh at those 
    who believed.
30. And 
    whenever they passed by them, used to wink one to another (in mockery);
31. And when 
    they returned to their own people, they would return jesting;
32. And when 
    they saw them, they said: ‘Verily! These have indeed gone astray!’
33. But they 
    (disbelievers, sinners) had not been sent as watchers over them (the 
    believers).
34. But this 
    Day (the Day of Resurrection) those who believe will laugh at the 
    disbelievers”
[al-Mutaffifeen 
    83:29-34]. 
So you should not worry 
    about their mockery, for Allah will bring them to account and Allah will 
    tell them what they used to do. 
What the person mentioned 
    has to do, if he has knowledge and is religiously committed, and he has 
    evidence to refute those who differ with him, is to quote his evidence and 
    explain the truth he has, and leave slander and mockery to people of a lower 
    status. 
Shaykh al-Islam Ibn 
    Taymiyah (may Allah have mercy on him) said: 
Responding by merely 
    reviling and shouting is something that anyone can do. If a person engages 
    in a debate with the mushrikeen and the People of the Book, he should 
    mention proof to highlight the truth he believes in and the falseness of 
    their beliefs. Allah, may He be exalted, said (interpretation of the 
    meaning): 
“call to the way of your 
    Lord with wisdom and goodly exhortation, and reason with them in the best 
    manner possible”
[an-Nahl 16:125]
“And argue not with the 
    people of the Scripture (Jews and Christians), unless it be in (a way) that 
    is better”
[al-‘Ankaboot 29:46]. 
If a person is debating 
    with one who uses foul language, even if he belongs to a group that is known 
    for extreme bid ‘ah, such as the Raafidis, then all that he has to do is 
    present his proof and avoid saying anything that is of no benefit.
End quote from Majmoo‘ 
    al-Fataawa, 4/186-187 
Secondly: 
With regard to the ruling 
    on shunning him and not greeting him or accepting his invitation, it should 
    be noted that the basic principle is that it is haraam to shun a Muslim for 
    more than three days, but that applies when the shunning has to do with 
    personal or worldly matters. 
But if the shunning is for 
    a religious purpose, such as shunning those who promote innovation or those 
    who commit evil and immoral actions, then in these cases we should examine 
    the Islamic purposes that may be served. If it is thought most likely that a 
    shar‘i interest will be served by this shunning, such as making a follower 
    of innovation give up his innovation, or make people disperse from around 
    him, or reducing the numbers of those who are deceived by him, or weakening 
    the spread of his innovation, and other shar‘i interests, then in that case 
    shunning him is prescribed. 
Similarly, it is prescribed 
    to shun those who follow innovation, especially those who open practise it 
    or promote it, so as to protect people’s religious commitment from being 
    affected by any of the specious arguments of the innovators or lest anything 
    of what they say take root in his own heart, especially if he does not have 
    sufficient knowledge to protect him against that. This is the principle that 
    was followed by the righteous early generations. 
Al-Baghawi (may Allah have 
    mercy on him) said: 
The Sahaabah, Taabi‘een and 
    their followers, and the scholars of the Sunnah, followed this principle and 
    were unanimously agreed on opposing and shunning the people of innovation.
End quote from Sharh as-Sunnah, 
    1/227 
See also the answer to 
    questions no. 22872 and
    47425.