If you clicked the link, you'd find out that no D presidential nominee, except Carter, had less than 60% of the Jewish vote. Now that isn't "monolithic" but it is, or was, a strong component of the D coalition. Losing this district, and performing so badly in a Jwwish area without a large Orthodox population, is a very bad sign for Obama in 2012, even if, as the D's are saying, this is about "Jewish issues."
BTW: The black vote was not as strongly D during the same period.
My point is about using special elections to predict future general elections, it just doesn't work, because special elections can be very unpredictable. This isn't a partisan thing, I wouldn't use a Republican losing a special election to predict anything either.