What is the ruling on oppressing the People of the Book, and what are their guaranteed rights in Islamic Sharia? Is preventing their oppression considered part of the forbidden loyalty?

Islam is a religion of justice, and it commanded its establishment with everyone. It also commanded kindness in dealing with the People of the Book, and it is not permissible to wrong them or assault them. The Prophet, peace and blessings be upon him, said: "Whoever kills a mu'ahid (person with whom a treaty has been made) will not smell the fragrance of Paradise," and "Beware, if anyone wrongs a mu'ahid, or diminishes his rights, or burdens him beyond his capacity, or takes anything from him without his consent, then I shall be his adversary on the Day of Judgment." Justice and kindness towards them are not considered mawalah (loyalty/alliance) to them unless accompanied by an inclination of the heart or affection.