God’s blessings on Jews often provoked jealousy. That’s it in a nutshell. When burning with jealousy, it’s easy to come to grandiose accusations.
Jews lived in Cochin, India for 2500 years and no pogroms, no attacks by local Hindus. Nothing
The Early and High Middle ages (until the 11th century) saw few Jewish persecutions compared to post the Black Death.