Sorry, but no... you can't play the "X religion has caused more damage to the world than Y religion" game. Islam caused the Dark Ages now too? Did it also cause the inquisitions and burn scientists at the stake?
Yes, Islam did have a negative impact throughout the Middle Ages and it might have been one of the causes of the Dark Ages, but it wasn't the main reason.
Many religions have caused A LOT of damage throughout history, and so have secular regimes like communism and fascism.
I'm saying this as a Christian, even though I don't really practice the rites. I know Islam isn't really popular on these boards (or maybe even the world) nowadays with everything going on with the ISIS, but COME ON, there's a limit to how much you can bash a religion and defend another.

I realize the General Boards is mostly a place where members with similar views come to vent and let off some steam, while agreeing with each other and those who don't are sometimes ganged up on or chased off the (General) boards. I accept it, it's the way it works here so whatever, but if I can be brutally honest, I must say I've also read some of the most ridiculous and extremist opinions in here that I've ever heard in my life, but as I said, I usually take them with a grain of salt because I think they're mostly venting and not 100% serious. (I'm not even talking about the theory you posted Faithful, if anything that might be plausible.)

Anyway my only suggestion to the members here is to be a little more open-minded in debates and trying to see things from different perspectives. However, I agree that with topics like politics and religion it's useless debating since nobody will change their mind, which is why I decided not to post anymore on these boards in such topics (and I don't think I'm the only one) And I know there's also trolls who just enjoy getting a reaction out of someone, but still I think it's important to be a little more friendly and respectful, regardless of somebody's views.
Sorry for the rant, just wanted to get this off my chest as I've seen a lot of hate on this board and it's not pretty.