The Qizilbash were stopped from worshipping his father by Tahmasp because he believed that it was a form of idolatry and that it was forbidden in Islam. Tahmasp also believed that it was important to maintain the unity of the Qizilbash and that worshipping his father would divide them.
The Magnificent Reign of Tahmasp I: Uncover the Untold Chapters of the Safavid Shah's Legacy