So their must be an aqeedah behind this nara same as their nara for Rasoollullah
I suppose ali is made of noor then... the shias here have this practice of "arbain" where they commemorate Imam Husayn's (ra) martyrdom on the 40th day after ashura. this year a local brelwi imam joined in the festivities (i dont believe there was any self mutilation). but interesting that some brelwis resemble shias in that regard