Is hating the style of a teacher who shows intense abhorrence for those who commit abominations, and feeling burdened by the obligatory letting down of the beard, included in Allah’s saying: "That is because they hated what Allah revealed, so He rendered their deeds worthless"?

The perfection of faith necessitates loving everything that the Messenger brought. However, a natural dislike for a teacher's style is not considered disbelief (kufr), especially since disliking a sin does not require showing a frown or distress; rather, it may involve smiling to endear the wrongdoer to what is good. It is recommended to ward off the whispers of takfir (declaring someone a disbeliever), to be constant in prayer, to distract oneself from these whispers, and to consult a psychiatrist.