There are no jews in ck2 because there were no jewish rulers in th ck2 timeframe.
And yet landowners arent the only characters in the game. Theres several people in your court, some of them working working for you. Like this guy:
Don Judah Abravanel was treasurer and tax-collector under Sancho IV (1284–95) and Ferdinand IV (1295–1312). In 1310 he and other Jews guaranteed the loans made to the crown of Castile to finance the siege of Algeciras. It is probable that he was almoxarife ("collector of revenues") of Castile.
So where's my jewish castillian money maker eh?

Jews were in the retinues of several medieval rulers, mostly in iberia and the muslim word, but not exclusively. All I ever wanted is for a jewish courtier to pop up in my court from time to time, you know, just like the conveyor belt of lowborn women that tend to appear in there, only with some actual usefulness to me. In the end of the day we wont come to an understanding so yeah whatever, thats what mods are for.
All I ever said is that a) jews were not so absent as the game seems to suggest and b) its a puzzling decision to cherry pick one religion out of so many to not include in the game when everything else under the moon that makes even marginal sense is in there (hi zoroastrians), and the "why bother going through the trouble of adding a whole new religion" falls flat when I, an amateurish modder at best, can add a new religion and 3 cultures with phony names in under an hour (plus whatever time it takes to do the symbol, that I cant do). For good measure one only needs to look at how many religions Lux Invicta added.