Is he who performs an act of worship whose origin is for other than Allah, and who did not originally intend it for Allah, considered a polytheist guilty of the major shirk that expels one from the fold of Islam?

Performing any act of worship for other than Allah the Almighty is major shirk (polytheism) that expels one from the fold of Islam, such as vowing, sacrificing, and supplicating. Allah the Almighty said: "Say, 'Indeed, my prayer, my rites of sacrifice, my living and my dying are for Allah, Lord of the worlds. No partner has He.'" And the Prophet, peace and blessings be upon him, said: "Allah curses whoever sacrifices for other than Allah." Major shirk is to direct worship or part of it to other than Allah, such as supplicating to the dead, seeking their aid, or vowing to them.