...Finally, traditional Christian doctrine has always blamed "the Jews" for the death of Jesus. But how can this be true since it is only by virtue of his death on the cross and subsequent resurrection that salvation could have ever been introduced into the world in the 1st century? One should argue the contrary, that the Jews who arranged for Jesus to be crucified did the supreme service to mankind according to Christian belief!
That's a fair question, I think.
First, I don't see anything in the New Testament where Christians are told to, or given license to, persecute Jews. I mean, the early church was completely Jewish. And Jesus himself was, and still is, Jewish on his mother's side. And Paul says:
Then what advantage has the Jew? Or what is the value of circumcision? Much in every way. To begin with, the Jews were entrusted with the oracles of God.
So I see no New Testament justification for persecuting Jews.
Otoh regarding the people who were involved in actually killed Jesus, I see three instances where he does blame them for their deeds.
First, here are his words about Judas Iscariot:
The Son of Man goes as it is written of him, but woe to that man by whom the Son of Man is betrayed! It would have been better for that man if he had not been born.
So even though a betrayer was part of the plan, the man himself was required to pay for his sin, just like anyone else would have.
Second, in the parable of the vineyard and the tenants he also blames the religious authorities in Jerusalem for his death. After all, they did instigate a riot to force Pilate's hand.
Third, he told Pilate that he was sinning, adding that his sins were lesser than Judas'.
So if Jesus himself pronounced them sinful, and he was the one who suffered, that's good enough for me.