I'd say the emphasis is more on professionalism. It's been a long time since Jews were primarily agricultural for many reasons (http://www.slate.com/articles/arts/everyday_economics/2003/0...). That combined with the fact that Christianity (for a long time) didn't allow loans with interest, so Jews filled in that role (http://en.wikipedia.org/wiki/Loans_and_interest_in_Judaism).

I don't know why this is on HN at all, however. When I was surprised at the supreme court ruling on gay marriage not well covered on HN (I thought the liberty angle made it appropriate), people seemed to think otherwise (https://news.ycombinator.com/item?id=5949827).