You would have to ask Muslims in America and Europe, where no civil authority can put them to death for apostacy, why they continue to worship the one same God as the Christians do.
Allah is NOT the Christian God! If Allah was, why would he put a curse upon all Christians and Jews?
"Fight those who do not believe in Allah And the Jews say Ezra is the son of God; and the Christians say Christ is the son of God; these are the words of their mouths; they imitate the saying of those who disbelieved before; Allahs curse be on them; how they are turned away!" (Koran 9:29-30)