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'm not out to bash any religion and there's no reason for you to take my posts that way. This is coming from several historians, not from me. The Islamic conquests had an impact. Not the only impact, but a major impact. I don't see why that's hard to accept. Also don't see the need for the sarcastic responses about the Inquisition, etc. Really don't understand why you're so offended.