Don't get me wrong, Religion can play a role in war, But I wouldn't say it was the most major starter, (Maybe the 3rd biggest war starter)We had wars over terrorism (Which yes I'll kinda count as a religious issue because seemingly most terrorist associate killing Americans with a religious reward like I think 60 ******s or something, They don't state which gender so hope they like it in the bum if they didn't get what hey was expecting). But generally speaking not many wars was brought by religion itself. Biggest war probably with a religion aspect in recent history was WW2 ( I say that because Hitler believed Germans was superior and teeecchhnically it was religious due to it's connection to Jews later on when it started, Even though it technically didn't start because of Jews but Hitler blamed Jews so they technically mads it a slightly religion issue) but real cause of it WW2 happened in WW1 being the treaty of Versailles.

However bigger things for wars usually happen before hand, Like North Korea and America with issues between them. Fighting for resources. Preventing spread of communism. Even assassinations caused one of the biggest wars in our time (WW1 with the Archduke ).

But generally speaking Religion plays a role in war time to time, But I'd hardly say it is the biggest culprit. Possibly 2ND to 3rd largest issue. But hardly the main reason