In reality, Jesus was against religion, all religion, Jewish or otherwise. In his movement, there were no sacred priests, pastors, places, or proscribed religious practices (only love was its guide).[1] In Christianity, all this came later (Frank Viola, Pagan Christianity). Jesus announced that the Jewish Temple, along with its Priests and sacrificial system, was about to become unnecessary. It would be destroyed and a new way of worship was coming, and had come, where it didn't matter what place people worshiped, but only the state of one's heart. (John 4:21-24). Jesus did not come to replace the Temple with a new Christian system, but to instill what Garry Wills calls "a religion of the heart." (Wills, What Jesus Meant, page 76).
Jesus didn't found a church. The word translated "church," ekklesia, merely means a gathering of people. The same word is used to describe a mob in Acts. Jesus and other New Testament writers describe gatherings of people that were non-hierarchical. They met in homes not church buildings. They were not led by pastors or apostles ('apostles' means ones who are sent, and could include women), let alone professional clergy, but either were self-regulating or facilitated by a egalitarian plurality of elders--unpaid, non-professionals. Where two or more are gathered in the name of Jesus, Jesus said, he is present. This is the meaning of the original "church." The notion that Jesus founded a Church on Peter or otherwise and/or began an apostolic succession is a myth that began centuries later (see Wills, What Jesus Meant and Robin Meyer, The Underground Church). The practice of assigning bishops did not begin until the second century. All the other church practices we know of from buildings, to altars, to choirs, to worship teams, to sermons, to statements of faith, etc., arose in the centuries after Christ (see Viola).
No, Jesus did not found a new religion called Christianity, nor a new institution called Church to replace the Temple or synagogue system. He came to demonstrate the love of God and announce that "the reign of God" (misleadingly translated 'Kingdom of God') had arrived and would be growing--and in a way that would welcome and include all people and not be proscribed through a religious system. So, why do we have churches, denominations, professional clergy, church planting, and a mentality that Christianity is a religion began in the first century?
[1] Many demonstrate historically that things like communion were instilled later. The "Lord's meal" was merely a Jewish custom that Jesus said "as often as you eat it it, remember me" and didn't proscribe a schedule for it nor command it. As for baptism, that appears to mirror the Jewish custom of ritual cleansing and many argue it was not technically a legalistic prerequisite for conversion or salvation that it has become.
