> The bloodiest wars were not religious, or I should say, not traditionally religious

The bloodiest war fought on European soil, right up until World War One, was the Thirty Years' War. The world wars' higher death toll can be attributed to 20th century technology; the Thirty Years War was fought with 17th century weapons yet still led to the death of 5-8 million people. And sure, while there were political motivations involved - you could say the same of any religious war, including the Crusades - the driving force was the schism between Protestants and Catholics.