The problem is, to my limited understanding, that people live in their very own Matrix. (In fact, the movie is a big metaphor, especially the 30 first minutes.) It's been called by many different names though, like 'sleep', it's also been called a prison. It's a place where automatism and 'personality ego' rules. It's a place where you can be seemingly happy, yet everywhere you look everything turns into shit and there are only glimpses of real, genuine emotion. One could say that wars and divorces are due to "human nature" but really, it's due to living your personality construct. Growing it is part of human nature, though. Then you 'must' grow out of it.
The goal of religion and all spiritual activity, such as meditation and prayer, living in isolation or monasteries is to free oneself from the crazy automatism that rules your life. This is why millions and millions of people throughout the ages has devoted their lives to such activities. Religion is a tool for people to work with, most people have it wrong - it's not meant to be a "follower-cult". I hope no-one found that offensive, but I believe it's important to question religion and to consider it more like a toolbox filled with wisdom and metaphors that's meant to be used to uncover truth. It's very hard to discover your prison on your own and much harder to escape it. Religion is a toolbox to help people who have discovered their prison, and everyone else to live a more honest life. Many people 'instinctively know' that they can live a more honest life with religion, but very few know why.
As you unveil personality, and learn to decide for yourself - instead of repeating the same patterns without notice - you see something. It's an aspect of "God". I believe people see different aspects of the same thing > multiple religions with different "Gods" - but they are really the same thing, from different perspectives. It's something like what's covered by the enneagram, a 4 would see beauty in everything and that would be one aspect of God. A 2 would see love. That's why one religion focuses on love, and another on something else.
This is, to me, the only logical reason why multiple religions exist. They see different aspects of the same thing. Else, you'd have to come to the conclusion that religion is bogus - which is where I was a few years ago. But now I think differently, as explained above. Also there are some beliefs like Gods in nordic mythology that probably doesn't have any truth to it. It's quite possible that the toolboxes was made into bibels and qurans and such to spread them as far as possible.
There may be crusades and holy wars but that's not due to religion. I believe the positives win over the negatives. It's not religion that causes holy wars, it's people who do not follow their inner qualities and ironically their very own religious teachings. It's because people are automatized and blind followers of their personality. Wars exist anyways, religion is one way to salvation. It's hope to humanity. It's a necessity.
That's the purpose of religion.