Why do Jews repeat tell Christian’s lies as truth?

Honorable Rabbi, with all respect please consider... You wrote: "On a more down-to earth level, Christianity, despite elements it has incorporated from Judaism, worships a Jewish sinner who lived at the time of the Mishna as god. Although the church proclaims that it worships the G-d of Israel, the G-d of Israel is most certainly not a person. " This is standard-type practice amongs Jews and esp. rabbis and I’d like to know why? Why do we as Jews, assume the story/myth of Xtianity as told by Xtian goyim is true? Moreso, why do we even assume Yishka was a real person? Finally, if he was real, isn’t it forbidden to accept a goy’s word to convict a Jew, esp. concerning something so grave as blasphemy and idolatry? If he was real (which no Jewish authority has ever confirmed nor denied) then suggesting that he is a Jewish "siner" is based on their mythylogical fabrication and not the required halakhic standards applied by a beit din. In fact, the convicting beit din would have to be on record and there is no such trial of Yishka or his followers recorded in our mesorah. (references in the Talmud to a Yishka/Yshu are not conclusive, and there is no ruling that the 2 that are spoke of are even the same person, let alone the one goyim claim to have been a real Jew. the church itself didn’t even begin the "Historical Yishhka" movement until late in the 5th century, a fact that seems to elude so many learned Jews.??) Just like we can not afford to call terrorists "activists", Arabs our "cousins" or Israel "palestine", so too we must be rigorous and shomer regarding the most horendous religion to ever persecute the Jewish people in history. Arafat has nothing on the Pope and suicide bombers haven’t even scratched the surface of the crusaders. (please edit any/all you wish)

As you mention in your question, the Talmud, most notably in the uncensored editions of Masechet Sanhedrin, refers to the Jewish sinner worshipped by Christians. Maimonides, among others, mentions him both in Hilchot Mlachim 11,4 and in Iggeret Teiman where he writes: "The first to discover this approach [=to pretend that he received a Divine mesage that could serve as an alternative to the Torah] was Jesus the Notzri, ... he led people to believe that he was a messenger of G-d sent to explain questions in understanding the Torah and that he was the Mashiach promised us by the prophets. The explanations he gave were such as to annul the Torah in its entirety and all of its commandments, permitting all that it prohibits, as was his intent. Our sages of blessed memory recognized his intentions before his fame spread within the Nation and they did to him what he deserved... After a long time a new religion originated among the descendants of Esau [=the Romans] and they attributed it to him though this religion was not his intent". Maimonides here like other Rishonim and Acharonim who refer to the question, base themselves on Jewish rather than Christian sources and in no way do they minimize the animosity of the Christian Church to Israel or give credence to Christian traditions.