There is a lot of resistance to the idea that Jesus was  a regular "Jewish Tzadik." Part of the reason is group identity. In order to be Jewish one must not have a good opinion of Jesus. The slightest positive statement about Jesus is enough to nullify one's credibility once and for all and to be labeled the worst of all terms "a missionary".

Another reason is the history of the crusades. That is in fact a good reason even if not sufficient.

Another reason is misunderstanding. Even though Paul did have this idea of nullification of the commandments that is clearly the exact opposite of open statements of Jesus himself.
There is also the mistaken idea that people worship Jesus and identify him with God which is all one big misunderstanding of what he was saying. The Trinity is not anything that he would subscribe to as gone into detail in the Trinities blog