I think todays Jews reject Jesus due to the corrupt version of monotheism that the church preaches...
Well, we are talking why the Jews living at the time of Jesus, rejected Him.
If you investigate Jewish Traditions, and Torah, there are signs given for Messiah.Theses signs are:
"The Messiah will arise out of an unknown city. He shall sit upon the throne of David, and behold, He shall come with a sword of steel, and with a sceptre of iron shall He rule! He shall fulfill the law of the Prophets, He shall conquer the East and the West, and shall glorify His chosen people the Jews. He shall bring with Him a reign of peace, during which even the animals shall cease to be at enmity with man. For behold the wolf and the lamb shall drink from the same spring, and the lion and the doe shall lie down in the same pasture, the serpent and the mouse shall share the same nest, and all Gods creatures shall be at rest."
According to the Jews, Jesus the Christ fulfilled none of these conditions. Because:
"He came from Nazareth, no unknown place. He carried no sword in His hand, nor even a stick. He did not sit upon the Throne of David, He was a poor man. He reformed the Law of Moses, and broke the Sabbath Day. He did not conquer the East and the West, but was Himself subject to the Roman Law. He did not exalt the Jews, but taught equality and brotherhood, and rebuked the Scribes and Pharisees. He brought in no reign of peace, for during His lifetime injustice and cruelty reached such a height that even He Himself fell a victim to it...."
Why the Jews did not think Jesus fulfilled these prophecies? Because, they interpreted these signs literally and "outwardly" (similar to our Muslim friends!)
But Jesus did fulfill these Prophecies, in a spiritual sense:
"Although He came from Nazareth, which was a known place, He also came from Heaven. His body was born of Mary, but His Spirit came from Heaven [an unknown place]. The sword He carried was the sword of His tongue, with which He divided the good from the evil, the true from the false, the faithful from the unfaithful, and the light from the darkness. His Word was indeed a sharp sword! The Throne upon which He sat is the Eternal Throne from which Christ reigns for ever, a heavenly throne, not an earthly one, for the things of earth pass away but heavenly things pass not away. He re-interpreted and completed the Law of Moses and fulfilled the Law of the Prophets. His word conquered the East and the West. His Kingdom is everlasting. He exalted those Jews who recognized Him. They were men and women of humble birth, but contact with Him made them great and gave them everlasting dignity. The animals who were to live with one another signified the different sects and races, who, once having been at war, were now to dwell in love and charity, drinking together the water of life from Christ the Eternal Spring.
Thus, all the spiritual prophecies concerning the coming of Christ were fulfilled, but the Jews shut their eyes that they should not see, and their ears that they should not hear, and the Divine Reality of Christ passed through their midst unheard, unloved and unrecognized.
It is easy to read the Holy Scriptures, but it is only with a clean heart and a pure mind that one may understand their true meaning. Let us ask Gods help to enable us to understand the Holy Books. Let us pray for eyes to see and ears to hear, and for hearts that long for peace."
Bahá'í Reference Library - Paris Talks, Pages 54-57