Why do the People of the Sunnah call themselves the Sunnah, and does this name unite or divide Muslims?

Muslims were adhering to the guidance of the Prophet, peace and blessings be upon him. Then, innovative sects emerged, which necessitated the appearance of the title "Ahl al-Sunnah (definition)" (People of the Sunnah) to distinguish those who adhered to the Sunnah. They were named this due to their attribution to his Sunnah, peace and blessings be upon him, unlike the people of innovation who attribute themselves to a saying, a speaker, or an action. Ahl al-Sunnah do not attribute themselves to any specific person other than the Messenger, nor to any title except the Sunnah. They support the authentic Hadith (definition) and the Salafi traditions, and they call for unity, the unification of ranks, and the gathering of Muslims upon what the Prophet, peace and blessings be upon him, and his Companions were upon. Thus, they are callers to unity and holding fast to the rope of Allah, and they forbid division and discord.