Makes sense at face value. Generally speaking, religious minorities tend to perform better economically than the majority religious group(s) since they have to work harder to overcome institutional and historical hurdles placed in their way. So when they are persecuted, their economic productivity is reduced. Quite simply, they are either killed, flee, or are reduced to poverty. All of these affect economic performance. We see this today with the Christian minorities in the Middle East and Near East (Copts in Egypt, Syriacs in Syria, Assyrians in Iraq and Turkey, Armenians in Turkey, etc.).