Why did the Jews lie about Jesus?

[Fake Messiah]

Yeah, let's hear what 1 Cor. 15 has to say: "5 and that he appeared to Cephas, and then to the Twelve."

I mean from the start you can see that Paul is lying because there were only eleven, Judas having died.

The Twelve was a technical name, widely used in the Early Church, for the inner circle of Jesus' followers. There is more than a nod to the 12 tribes of Israel. Judas was fairly quickly replaced. 

Hence the capital letter, and the appropriate continued use even when there were temporarily 11 of them.

And yet Matthew 28:16, Mark 16:14, and Luke 24:33 have Jesus appear to the eleven.

I mean, listen, what you just gave was a purely ad-hoc argument and the fact is there is no reason that the Twelve that Paul mentions have anything to do with the Twelve apostles. For starters Paul never uses the word "Apostles" in his writings. Indeed, many scholars that take historical Jesus for granted don't consider that Jesus selected an elite corps of twelve already in his lifetime, rather that the Twelve were so constituted by a shared resurrection vision. One of the many reasons for thinking that is that Jesus himself almost never mentions the Apostles (quoted sayings of Jesus) but "the Twelve" rather occur in narrative sections of the Gospels. And even when in rare occasions when "the Twelve" are on Jesus' lips are doubtful, like Mark 14:20, Jesus says his betrayer is "one of the Twelve," but neither Matthew nor Luke, who follow Mark, have the phrase.

And, also, one other evidence that Jesus never had the Twelve was that the whole story of Jesus choosing the Twelve was clear rewriting of the Moses story when he chose the seventy elders: they both get a visit from their relatives who both have a suggestion that he was overworked and needed to share the burdens of leadership.

And also there is the problem with the names of the Apostles. The canonical lists of the Twelve do not agree in detail, nor do manuscripts of single gospels. If the Twelve were as important as church rhetoric would suggest, how is it possible that such uncertainty should exist even upon the point of who they were? Can we imagine early American histories in which the lists of presidents did not agree? And, of course Cephas of Paul's writings and Simon Peter are not the same character.