They go against sharee’ah and use as an excuse the fact that there are righteous people who do that
Question

                Some imams in mosques and professors of Islamic education, and others who are regarded as examples for other people, trim their beards – and some shave them altogether – and they let their garments hang too low. When you try to prove it, some people of weak character argue that these actions are haraam and they say to you: So and so is the imam of a mosque and he lets his garment hang too low, or So and so is a teacher of Islamic studies and he shaves his beard. 

We would like you to say something about such imams and those who are in similar roles, and the seriousness of what they are doing for themselves and for all other people.
Praise be to Allah.
    Firstly: 

    The fact that some of those who go against sharee’ah are 
    justifying what they do based on the actions of some imams of mosques or 
    some teachers of Islamic education, will not benefit them before their Lord, 
    because what is required of the Muslim is to follow the example of the 
    Prophet  (peace and blessings of Allaah be upon him), and it is not 
    permissible for him to put the teaching of anyone else before the teachings 
    of the Prophet  (peace and blessings of Allaah be upon him). Allaah says 
    (interpretation of the meaning): 

    “Indeed in the Messenger of Allaah (Muhammad
    صلى الله عليه وسلم) you have a good 
    example to follow for him who hopes for (the Meeting with) Allaah and the 
    Last Day, and remembers Allaah much”

    [al-Ahzaab 33:21] 

    “And (remember) the Day (Allaah) will call to them, and 
    say: “’What answer gave you to the Messengers?’”

    [al-Qasas 29:65]

    If the Sunnah of the Prophet  (peace and blessings of 
    Allaah be upon him) is clear, then it is not permissible for a Muslim to 
    ignore it because of the actions or words of some person. Imam al-Shaafa’i 
    (may Allaah have mercy on him) said: The people [scholars] are unanimously 
    agreed that if the Sunnah of the Prophet  (peace and blessings of Allaah 
    be upon him) has become clear to a person, it is not permissible for him to 
    forsake it because of the opinion of any person. 

    Secondly: 

    The one who has become an example for people must be more 
    careful about his adherence to the Sunnah and not going against it, because 
    the people will follow his example and will regard his actions as being in 
    accordance with sharee’ah. 

    Shaykh Muhammad ibn Saalih al-‘Uthaymeen (may Allaah have 
    mercy on him) said: 

    Hence the scholars have obligations that others do not, with 
    regard to acts of worship, morals and manners, and interactions with others, 
    because the people will follow their example, they will follow their example 
    completely. Some people will even sit by a scholar whilst he is praying – 
    for example – and take note of every single movement. When Ibn ‘Umar (may 
    Allaah be pleased with him) grew old, he did not sit muftarishan (sitting on 
    the left foot and holding the right foot upright with the toes pointing 
    towards the qiblah) in the prayer. One of his sons said to him: “What kind 
    of sitting is this?” He said: “My feet do not let me?” Look at how the 
    people watch the scholar and take note of everything he does, and even what 
    he does not do. Hence it is essential for the seekers of knowledge to be 
    good examples in all things, so that the people will respect them. End 
    quote. 

    Al-Liqa’ al-Shahri (introduction 
    to meeting no. 49). 

    Shaykh ‘Abd al-‘Azeez ibn Baaz (may Allaah have mercy on him) 
    said: 

    The scholar is known for his patience, his piety or awareness 
    of Allaah, his fear of Him, his hastening to do what Allaah and His 
    Messenger have enjoined, and his keeping away from what Allaah and His 
    Messenger have forbidden. 

    This is how the scholar should be, whether he is a teacher, a 
    qaadi, a daa’i who calls people to Allaah, or in any field of work. His duty 
    is to be an example of goodness, and to be an example of righteous deeds, 
    acting upon his knowledge, fearing Allaah wherever he is, guiding people to 
    goodness. So he should be a good example to his students, to his family 
    members, to his neighbours and others whom he knows, so that they can follow 
    his example in his words and deeds that are in accordance with the laws of 
    Allaah, may He be glorified and exalted. 

    The seeker of knowledge must be very careful and beware of 
    being careless about that which Allaah has enjoined, or of falling into that 
    which Allaah has forbidden, because he may be taken as an example in that. 
    If he is heedless, others will be heedless too. The same applies to the 
    Sunnah, and to makrooh actions. He should be keen to observe Sunnah actions, 
    even if they are not obligatory, so that he will become accustomed to doing 
    them, and people will follow his example in that. And he should keep away 
    from makrooh things and dubious matters, so that people will not follow his 
    example in that. 

    The seeker of knowledge has an important status. The scholars 
    are the elite in this life, so they have duties that others do not share. 
    The Messenger  (peace and blessings of Allaah be upon him) said: ‘Each 
    of you is a shepherd and each of you is responsible for his flock.” End 
    quote. 

    Majmoo’ Fataawa al-Shaykh Ibn Baaz 
    (2/312, 313) 

    2. and he (may Allaah have mercy on him) said: 

    Allaah says (interpretation of the meaning):  

    “And who is better in speech than he who [says: ‘My Lord 
    is Allaah (believes in His Oneness),’ and then stands firm (acts upon His 
    Order), and] invites (men) to Allaah’s (Islamic Monotheism), and does 
    righteous deeds, and says: ‘I am one of the Muslims’” [Fussilat 41:33].
    

    This verse shows us that the one who calls people to Allaah 
    must be a person of righteous deeds, calling to Allaah with his words, 
    calling to Allaah with all his actions. Hence He says after that “and does 
    righteous deeds.” The one who calls people to Allaah must call with his 
    words and with his actions. There is no one better in speech than this type 
    of person, those who call to Allaah with their good words and guide the 
    people with their words and deeds. So they become a good example in their 
    words, deeds and behaviour. 

    This is how the Messengers (peace and blessings of Allaah be 
    upon them) were: callers to Allaah with their words, actions and behaviour. 
    Many of those who are called benefit more from the callers’ behaviour than 
    from their words, especially the common folk and those with limited 
    knowledge. They benefit from the caller’s behaviour, good attitude and 
    righteous deeds in ways they cannot benefit from their words which they may 
    not understand. One of the most important missions of the one who calls 
    people to Allaah is to have a good track record, to be a person of righteous 
    deeds, to have a good attitude so that his example may be followed in his 
    actions, words and deeds. 

    This verse encourages and urges us to call people to Allaah, 
    and explains the status of the callers (daa’iyahs): they are the best of 
    people in word if they are sincere in what they say, and do righteous deeds; 
    they are the best of people in word and no one is better than them in word 
    at all. Foremost among them are the Messengers (peace and blessings of 
    Allaah be upon them), then those who follow them with insight until the Day 
    of Resurrection. End quote. 

    Majmoo’ Fataawa al-Shaykh Ibn Baaz 
    (3/110, 111) 

    We ask Allaah to set the affairs of the Muslims straight, and 
    to guide the daa’iyahs and seekers of knowledge to that which is in their 
    interests and in the people’s interests. 

    And Allaah knows best.