Well, many Christians still buy into the "Jews killed Jesus!" propaganda even though it was over 2000 years ago.
And as for Zoroastrians, it is still probably a stronger historic basis than for Christians, who persecuted Jews during the Spanish Inquisition and slaughtered them (and Muslims and Orthodox and Miaphysites) during the Crusades.
I don't know why people still by into this crap.
Go read the actual writings produced around the time of the Crusades - leaving aside the nutjob contingent who started killing Jews (the Pope put a stop to that, irrc threatening people with excommunication in addition to the secular courts) the Crusades were not, by and large, a religious bloodbath - certainly not for Christian-on-Christian violence.
The actual reason that Christians and Muslims borrow money from Jews is that they have prohibitions against money-lending (as do Jews amongst themselves).
The Jews, Christians, Muslims and Jews are all united by their refusal to worship any other Gods - Pagans are all Polytheistic to one degree or another, they allow for variants in worship and Pantheon.
Essentially the first group say "Our God is the True God" whilst the second say "I do not worship your God - but that is because my God is better".
As to why Pagans don't get access to Jewish courtiers - it's because Jews are "atheists" in the Classical sense and their concept of a single "jealous" God would be considered as dangerous as the Muslim or Christian one.