The origin of Christianity is still a grey area to me. How would you have responded if, after Muhammad was driven out of Mecca, his remaining followers in Mecca were then called Mohammedans and they introduced a divergent interpretation of Islam? This would have resulted in 2 biblical religions Judaism & Islam vs 2 divergent religions, namely Christianity & Mohammedanism. Do you think in this instance the Quran would also have referred to Mohammedanism as a religion?Christians revere the Hebrew prophets, but exclusively follow what they believe to be the teachings of Jesus Christ. Christos means "anointed/chosen one", and this is where the term Christian comes from.
I'm of the opinion if Jesus was accepted as a prophet from the Jews to the Jews, Christianity wouldn't have existed today as the followers of Jesus would have been known as Jews and not Christians.