What are the reasons for the existence of many sects in Islam, for Islam's recognition of Jesus (peace be upon him), and for the obligation of hijab on women but not on men?

Islam is one religion, free from contradictions. The differences that arose among Muslims occurred due to misunderstanding and ill-intent. Allah has legislated for us protection from disunity by following the companions in their understanding of the Book and the Sunnah, and by devoting religion purely to Allah. Islam is the religion of all prophets, and Jesus, peace be upon him, is one of them. The religion is the Oneness of Allah and believing in His prophets. The hijab is an obligation upon women to protect them, safeguard their honor, and ward off temptation from society, because women are the more vulnerable side, and their veiling protects them from aggression and indecency.