The only convincing reason I know of is that while from the middle ages onwards, Christians (and Muslims) were banned in the bible from issuing loans with payab

The only convincing reason I know of is that while from the middle ages onwards, Christians (and Muslims) were banned in the bible from issuing loans with payable interest, the book of Deuteronomy had a get-out clause for Jews: they were only barred from issuing such loans to their 'brothers. ie. eachother This would have three logical consequences: Jewish people becoming masters of finance; Jewish people helping their own community over others; and Jewish people obtaining all the disrepute that comes with being a loan shark. You can see how all 3 things would breed resentment/jealousy from other ethnic groups. Shakespeare's The Merchant of Venice cuts to the heart of the matter. Shylock offers the financing needed by the protagonists - but such financing by necessity comes with brutal collateral ('a pound of flesh'). People see the heartless lender exacting payment, but not the underlying laws of economics.