Jewish Problem Sources: [the Jews] “killed both the Lord Jesus and the prophets”

Anti-Semitism was long justified by passages like this one from I Thessalonians: the Jews “killed both the Lord Jesus and the prophets.”
Anti-Judaism arrived with the first documents of Christian scripture and, through generations of theologians over the centuries, were transformed into today’s secular Jewish Problem. Which raises an obvious question: What in Judaism could so threaten Christianity as to represent Jews as a “problem” demanding “solution? As Rosemary Ruether described in Faith and Fratricide (p.94), 
“The anti-Judaic tradition in Christianity grew as a negative and alienated expression of a need [for early Christianity] to legitimate its revelation in Jewish terms.” (emphasis added)
In other words, had the new religion taken any of several alternative routes available in its early centuries (Marcionism, for example, rejected both Jewish scripture and the “Jewish god”); had Christianity, comprising Jewish and Pagan features, moved more openly towards pagan Man-gods such as Dionysus, Judaism and Jews would likely still have faced prejudice as “Other,” outsiders to the dominant society/religion. But living peacefully among Christians as “Jews” would not necessarily have constituted a fundamental threat to Christianity. Christian society might still have reacted with occasional violence against the Jewish “stranger” in their midst minus such “gospel” references as Jews as “Christ-killers” and “children of Satan,” but minus gospel polemicizing against “the Jews,” demonizing them as deicides, the later anti-Judaic stereotypes born in the Middle Ages that dogged Jews over the centuries and inspired the Holocaust likely would not have emerged. 
As Paula Frederickson reminds, until about two hundred years ago nearly everybody considered scripture “historical.” And even today many believe it to be “the inerrant word of God.” Scholarly debate such as that spawned by Christian guilt immediately after the Holocaust, had little impact on religion or faith. Not even religious authorities can easily change a belief system based on tradition centuries-long. In 1965, for example, the Vatican adopted Nostre Aetate which, in part, exonerated present day Jews from the curse of Matthew 27:25, “His blood be upon us and our children!” And for years following its adoption antisemitism among Catholics actually increased. 
Two-thousand years after “Matthew” the 2011 Anti-Defamation League poll of antisemitism among non-Jewish Americans found that nearly one-third surveyed continue to believe that, as described in Paul and the gospels, Jews are collectively responsible for the death of Jesus: 
“A surprisingly large number of Americans continue to believe that "Jews were responsible for the death of Christ.” 
Thirty-one percent (31%) of Americans agreed with that statement.”