If religion did not exist, it's a hypothetical question because religion has been a part of human history for a very long time. As you've pointed out, religion has played a role in numerous events and has had both positive and negative impacts on humanity. For me, the question isn't about how life would have been if religion never existed. Rather, the more intriguing question is, how can we envision a future without religion and without its influence on human interactions on Earth? Ponder that!