I guess it is human nature to try to stand out , to be different. Now a days teen agers do it by being Gothic, emo or punk.
Some grown ups do it by adopting a certain hair style or fashion in clothes.
Same way groups of people want to stand out from the crowd of Muslims by declaring themselves as , Shia , Sunni , Ahmadi, Aga Khani, Khojay, Deo Bandi , Brailvy, Jafri, Hanafi, Shafa-e, Hunbli, Maliki, Ahal-a-Hadees, Wabahi etc etc .
If a Mullah does not differentiate himself how can he start a new Masjid and live happily ever after. The followers being so ignorant about the true spirit of religion do not put their time and effort to understand the true religion and blindly follow what Mullah tells them. There are so many ignorant who will say , it is not easy to understand Quran , Hadees, Religion , so they outsource the contract of understanding religion to Mullah. Mullah abuses the power so vested into him .
Not all Alims are Mullahs and not All Mullahs are Alim a deen , there are many Alim a deen who do not believe in sectarianism in Islam . I admire them and respect them.