Slight correction: Jews were religiously prohibited from charging interest... to other Jews. (As I understand it, and someone please correct me if I'm wrong: not being Jewish myself, my information is second- or third-hand for most of this). Which is part of why they ended up being moneylenders to the non-Jews they lived among. Another part was that, as people who often had to pack up and move, fleeing from armed groups (who may or may not have had the official sanction of the local authorities, but usually did have their unofficial sanction), Jews tended to gravitate towards professions where most of their wealth was portable. Farming? Nope, get chased off your land and your profession is gone. Blacksmithing? Your tools and your stock-in-trade are too heavy to move quickly. Also nope, not if you expect to need to run for your lives at very short notice. But moneylending, or selling gold and jewelry? That works. Grab one or two chests and throw them onto the cart, and you've preserved most of the core of your business, even if the mob torches the shop and any tools that were impractical to move.

So Jews ended up gravitating towards being jewelers, bankers, moneylenders, and so on. All of which, yes, did feed into stereotypes.