The Christian faith did the same, the whole point of the Crusades was to expand the Christian faith and their power. They were told G-d had supported it so they could kill as many people as they wanted, including innocents, and they would dine in heaven for their service and all sins would be forgotten.

When Jerusalem had surrendered because the Christians promised no harm would come to them they then proceeded to slaughter every single innocent life (including some Christians) because G-d 'allowed it'.

Every faith has a terrible side to it, and if we are to label the religion of Islam as a violent one then by the same token everybody who is Christian should be labelled the same.

The Quran has violent verses, but there is historical context to them such as speeches said before battle there were the teachings of Mohammed not Allah, Islam in a majority is peaceful but due to the conditions these people live in it is very easy for them to be talked into believing a false faith because they have nothing else to turn too, when you hate Islam and Muslims then they have won.

One thing to note, all of these religions follow the same G-d just different prophets (Allah = God) so really they are killing people who actually do believe in their same god and that doesn't make much sense, this is how you know these people don't think properly and don't understand their own religion.