Back then the inhibition level for violence was much lower than it is today, even in the Middle East. Also the Christian culture went through various changes, i.e. the French revolution and enlightenment, which have never occurred in Islamic cultures. Even the kind of enlightenment in the Golden Age were deeply motivated by religion and were hence inherently unstable and also limited.

I am talking about the cultural difference today, not in the past, about aggression and harmful traditions occurring in reasonably stable and educated middle classes. Note, that I am not trying to whitewash the past of Christianity; both sets of beliefs are bad in that they have or had the potential to produce fundamentalism and badly informed decisions, but I am just arguing for a qualitative difference between Islam and Christianity (especially today's Christianity and Islam), i.e. one is much worse than the other. Today's Christianity does not produce anything as Islam does in other troubled regions such as African countries, even though these people would be in their 'right' to take vengeance for e.g. centuries of slavery, right?