Is shiism really about islam or more about persian glory?

Shia basically believe that God choose Ali son in law and cousin of the Prophet to be the spiritual leader of all Muslims after the Prophet and then this would go on in his family through his male descendants..many people from persian or iranian background are shias...this doesn't mean only Irani's are shia Muslims...they are spread all around the world...btw everyone has their own beliefs and shias believe they are true Muslims whereas Sunni believe that they are true Muslims ..we must not forget that we have to respect all religious beliefs as it is the teaching of the Prophet