Judais is not set as dominant in default (i have judaism and buddism by game not WB).
And yes it spreads too fast. Before i have reached Cristianity i europe was zorastrial and hinduistic, mideast hinduistic, russia zoroastiac, and china india and japan Judaist. Than Taoism founded by Shaka grew up in lots of cities, but only shaka remained Taoist. When Cristianity was funded by Cyrus, it had no "free" city to spread in Old World. America had no religion, and Islam was funded by Russia that grew in power.
But neighter Christianity not Islam had their state religion.