While i do not agree with all parts, i will just say that this is the assumed disadvantages of religion, not religion being a disadvantage. Meaning that, just because all these things might be true, doesn't mean religion is a disadvantage, because you haven't been fair about it's advantages.
Religion is supposed to be for most of those who follow it, the truth, or the teachings from their maker, or the explanation for the universe, or the guide to their thinking and morals.........
So, i can't judge religion that way, as in judge by it's perks and disadvantages, because this judgment is neutral, and not putting in mind the fact that religion is supposed to the truth for people who follow it. Also, if we assume that all your notes on the point we are at today are true, religion has nothing to do with it. Because it has always been there, so it could be something else that have put us in such position.
Also, war has many reasons, religion is merely one of the excuses that leaders have used to justify wars. Political struggles, greed, pride, conflicts of any kind are all reasons for war. Religion isn't, it is a tool that leaders use to justify their war by. I'll admit though, that surely some of the religious wars were because some people really believed that their religion or their God says so, but that is not enough to judge it or deem it as a bad thing. A lot of things can be used in a good or a bad way, so it is not enough a proof against religion, that some used it that way. Because others have used it well, and it gave them great satisfaction in their lives in so many ways.