“Why would an East African Islamic terrorist organization want to threaten one of their sympathizers?”
Haven’t you figured out yet that these people hate everyone?
They even hate each other.
They hate all non-muslems and all apostate muslems. In the muslem view if your father is muslem, then the child is muslem. Thus Nobama is muslem and his public statements that he is a Christian and not a muslem makes him apostate and thus must either return to the religion or be killed as an apostate muslem. Thus their justification of obedience to the laws of Islam.