Answer
Salam Dear Brother,
Thank you for your question and for contacting Ask About Islam.
To simply answer your question, Christians worship Jesus because they were brain washed by their churches to do so even though it contradicts their Gospel.
Before Prophet Muhammad’s message, so many religions have started as monotheistic, worshiping the true God, and have deviated over time; that’s why there was a need for a final message with a final revelation, telling people to worship one God, the Creator. It is the Muslims duty to convey this final message.
To answer your question indirectly, I just have to prove that Jesus was not God. God, the Creator, is different than His creation; they cannot be the same. So God does not turn himself into His own creation because their attributes are completely different.
For example, humans need to eat and when they do so, they discharge what remains which cannot be attributed to God. Humans live and die while God has no beginning or end since He is the one who created life and death.
It makes more sense that Jesus (peace be upon him) was sent as a prophet to guide the people of Israel as you have mentioned and the proof is in the Christian Gospel in Matthew 15, verses 22-24 and Matthew 21:11 as in the highlighted article:
[22] And, behold, a woman of Canaan came out of the same coasts, and cried unto him, saying, Have mercy on me, O Lord, thou Son of David; my daughter is grievously vexed with a devil.
[23] But he answered her not a word. And his disciples came and besought him, saying, Send her away; for she crieth after us.
[24] But he answered and said, I am not sent but unto the lost sheep of the house of Israel.
A prophet is usually sent to a specific nation and Jesus (peace be upon him) was sent to the Israelites. If he was God himself, he would have gone all over the earth, reaching every nation and tribe at that specific time.
Also the idea that God took the form of a human in Jesus (peace be upon him) is not mentioned anywhere in the Christian Gospel. However, the idea that God sent prophets to guide mankind which is much simpler to understand, is repeatedly mentioned in the old and new testaments and the Quran.
[And he said, Hear now my words: If there be a prophet among you, I the LORD will make myself known unto him in a vision, and will speak unto him in a dream.] (Numbers, 12:6)
As mentioned in the link above, Jesus’ followers called him a prophet per Matthew 21:11:
[And the multitude said, This is Jesus the prophet of Nazareth of Galilee.]
So his people called him a prophet; then why did the personality of Jesus changed from prophet to God according to most Christian denominations, clearly defying their own Gospels in all different versions, is a mystery to me.
Yes we have the history on how it happened, but why would modern Christians follow a creed that is contradictory to their Gospel’s teachings!? My guess is “blind faith”.
Please read: Did Jesus Claim that He Is God?
I hope this helps answer your question.
Salam and please keep in touch.