We blamed all Jews for crucifying Jesus, and invented Antisemitism
People do horrible things in the name of religion, and according to the United States Holocaust Memorial Museum, hatred against the world’s Jewish community started thanks to a falsehood written into Christian doctrine by early church leaders. It was the claim every Jewish person had a personal responsibility when it came to Christ’s crucifixion, and their continued suffering was punishment for past acts and for holding onto their faith.
It only got more horrible as other accusations masquerading as facts were piled on the hate-fire. By the 10th and 11th centuries, Europe wholeheartedly embraced the idea that other religions were a direct threat to Christianity, and hate escalated into “blood libel.” According to popular belief (via Moment), blood libel was a practice in which Jews killed Christian children, drained their blood, then used it either for ritual purposes, for baking, or for replenishing their own fluids. It was reported as absolute and undeniable fact. Cases date to 1144, when English Jews were accused of torturing and killing a boy named William. Jews in Italy were accused of killing a little boy named Simon in 1475, ultimately sentenced to death. Meanwhile, Simon was canonized, with the sacrifice as part of his backstory.
Blood libel is still a thing, and trials have been held from Russia to New York into the 20th century. And we all know what happened during World War II.