Why is it Called Christianity?

Haven't you ever wondered why it is called 'Christianity'? If the religion was all about 'Jesus' why isn't it just called 'Jesusanity' or some such name?

Let's start at the beginning. If the words of Rashi and Saadya are translated EXACTLY, you can see how each quotes his unacknowledged source, and then adds words of his own to reconcile this with the opinion of his own time. This work of separating components is part of what is called Source Criticism. When this has been done, you will then see that neither of them dared change what his source said, but that each of them was puzzled by it. You then have to show to what extent each one was willing to go against the view of his own time. This gives evidence of the strength of the survival of the older view, and shows that they partially AGREED with it, as you have seen for yourself.This faithfulness in transmitting puzzling statements is evidence of the use of an old document that was regarded with respect. Showing this puzzlement is another part of Source Criticism, since it is evidence of the antiquity of the source. After doing this, you then have to show precisely which bit of the Zadokite document they were alluding to. This is another part of Source Criticism. You will see why an EXACT translation of the Hebrew is needed, and an EXACT reference to the Zadokite Document is needed.
A different question. If Marcion used a Gospel of Luke, what was it like?
Don’t forget that Christianity has de-sanctified Jerusalem. This is a major theological doctrine. It can be connected with your theory very easily.
You may well wonder why I can look at all this with equanimity while remaining a Christian. Well, first, if you’re a Protestant, you have complete confidence that the pursuit of the truth must be beneficial in the end, and that whatever is puzzling will sort itself out. That’s why we don’t need the Pope or any other officials to filter out what might cause difficulties. Second, there is no point in carrying on too much over who was or was not the Anointed One, or Messiah. Many people could have been. The Jewish concept of what the term means is not the Christian one. Jesus wouldn’t accept the term, except from the Samaritan woman in John IV and from Peter right at the end, when Peter had been shown by the Holy Ghost what the CONCEPT was. As for Jesus being an Angel, that concept exists within Christianity, and is well documented. Don’t forget that Jacob was an Angel as well as a human. (I can give you a precise reference for this). If Jesus embodies Israel (which is a name ending in EL, as all names of angels do), then he must have been an Angel, as well as being human. Besides, Jesus predicted the destruction of the Temple, and as this prediction was an essential part of his work, and important for Christian doctrine, then it doesn’t matter that he said it forty years before the event. Both he and Agrippa would have believed that this destruction of the earthly Temple was necessary for the descent of the Heavenly Jerusalem or Heavenly Tabernacle, thus uniting Jews and Samaritans. Note that the Epistle to the Hebrews fuses the two concepts. The Christian order of service for Sunday morning often includes hymns asserting that Christ is High Priest in the Heavenly Tabernacle. One is right to point out that the religion is called Christianity, not Jesusanity. This has profound implications. Anyway, whatever might be in Evangelical hymnbooks, mainstream Christians don’t worship Jesus or Christ, which is why Maimonides declared the religion not to be polytheism, and in this he was following the Talmud.