Because they didn't.
Jews that followed the Torah, only worshipped one G-D.
That would be the G-D of Abraham, Issac, and Jacob. It certainly had nothing to do with jesus.
Hear O Israel, the L-rd is our G-D, the L-ord is ONE (Deut)
I am the Lord, and there is no other; apart from Me there is no God. ...so that from the rising of the Sun to the place of its setting men may know there is none besides Me. I am the Lord, and there is no other. (Isaiah, 45:5-6)
...I am God, and there is no other; I am God, and there is none like Me. (Isaiah, 46:9)
... so that all the peoples of the Earth may know that the Lord is God and that there is no other. (1 Kings, 8:60)
Turn to Me and be saved, all you ends of the Earth; for I am God, and there is no other. (Isaiah, 45:22)
This is what the Lord says
"Surely God is with you, and there is no other; there is no other God." (Isaiah, 45:14)
...The Lord our God, the Lord is one. (Deuteronomy, 6:4)
You are my witness--the words of Hashem--and My servant, whom I have chosen, so that you will know and believe in Me, and understand that I am He; before me nothing was created by a G-D, and after Me it shall not be (Isaiah 43:10)
... O Lord; no deeds can compare with Yours. All the nations You have made will come and worship before You, O Lord; they will bring glory to Your name. For You are great and do marvelous deeds; You alone are God. (Psalms, 86:8-10)
O Lord ...You alone are God over all the kingdoms of the Earth. You have made heaven and Earth. (Isaiah, 37:16)
... all kingdoms on Earth may know that You alone, O Lord, are God. (Isaiah, 37:20)
This is what the Lord saysyour Redeemer, Who formed you in the womb: I am the Lord, Who has made all things, Who alone stretched out the heavens, Who spread out the Earth by Myself. (Isaiah, 44:24)
Since ancient times no one has heard, no ear has perceived, no eye has seen any God besides You, who acts on behalf of those who wait for Him. (Isaiah, 64:4)
For this is what the Lord saysHe Who created the heavens, He is God; He Who fashioned and made the Earth, He founded it; He did not create it to be empty, but formed it to be inhabitedHe says: "I am the Lord, and there is no other." (Isaiah, 45:18)
...Was it not I, the Lord? And there is no god apart from Me, a righteous God and a Savior; there is none but Me. (Isaiah, 45:21)
See now that I Myself am He! There is no god besides Me. I put to death and I bring to life, I have wounded and I will heal... (Deuteronomy, 32:39)
...you may know there is no one like the Lord our God. (Exodus, 8:10)
O Lord... there is no god like You in heaven above or on Earth below... (1 Kings, 8:23; 2 Chronicles, 6:14)
Then Asa called to the Lord his God and said, "Lord, there is no one like You to help the powerless against the mighty..."(2 Chronicles, 14:11)
I, even I, am the Lord, and apart from Me there is no savior. (Isaiah, 43:11)
There is no one like You, O Lord, and there is no god but You, as we have heard with our own ears. (1 Chronicles, 17:20; 2 Samuel, 7:22)
There is no one holy like the Lord; there is no one besides You; there is no strength like our God. (1 Samuel, 2:2)
His wisdom is profound, His power is vast. Who has resisted Him and come out unscathed. (Job, 9:4)
For You are great and do marvelous deeds; You alone are God. (Psalms, 86:10)
Praise Him for His acts of power; praise Him for His surpassing greatness. (Psalms, 150:2)
You alone are the Lord. You made the heavens, even the highest heavens, and all their starry host, the Earth and all that is on it, the seas and all that is in them. You give life to everything, and the multitudes of heaven worship You. (Nehemiah, 9:6)
They will say of Me, "In the Lord alone are righteousness and strength."... (Isaiah, 45:24)
You were shown these things so that you might know that the Lord is God; besides Him there is no other. (Deuteronomy, 4:35)
... Is there any god besides Me? No, there is no other strong one; I know not one. (Isaiah, 44:8)
This is what the Lord saysI am the first and I am the last; apart from Me there is no god. (Isaiah, 44:6)
Who has done this and carried it through, calling forth the generations from the beginning? I, the Lordwith the first of them and with the lastI am He." (Isaiah, 41:4)