You are willing to grant me that criminals are criminals first. The problem is extreme behavior; it's not whether you fast during Lent or during Ramadan.

Christianity, as a state religion, had a bloody history for approximately 1500 years. (I'm not counting its first 300 or so years, before it became a state religion, because although that period was also bloody, the Christians were not the ones inflicting the injuries.) Only over the last, say, 250 years have we escaped the spectacle of people being imprisoned, tortured, starved, "re-educated", burned alive, and executed in other ways because they were not Christian, not Christian enough, or not the right kind of Christian.

It stopped being that way for three very good reasons:

1. The rise of scientific thought. Christian churches had an embarrassing tendency to try to contradict science when scientific conclusions were inconvenient for the churches. (Some of them are still trying to do this. Cf. "evolution".) After they made themselves look stupid and fallible in this area, the door of doubt opened up to the wider room of human thought. The churches had to rediscover humility and admit they didn't know everything (which educated people had already figured out) in order to retain what credibility they had left.

2. The spread of literacy. People are more liable to be critical of their leadership when they have more information available to them, and when they can understand it. Although there are very many literate bigots in this world, the trend has been away from bigotry as away from ignorance with the rise of literacy among the population. This is especially true when literacy reaches women, who are the first teachers of their children.

3. Because of the two previous factors, a strange little confederacy with a history of religious strife decided that it would apply rational thought to its experiment in government and make religious freedom a cornerstone of its law. The experiment worked, and while the citizens continue to yell at each other, and occasionally commit religiously-motivated crimes against each other, the state has not burned anyone at the stake for heresy in a very long time. Other nations took heart from this experiment and have endeavored to include some features of it in their own experiments.

The rise of the nation-state has some role in there as well, but since the rulers of such states initially used religion as an instrument of statecraft, which is to say, violence and terror, this role was more peripheral to the removal of Christianity's fangs.

Islam is a younger religion than Christianity. It has a way to go in this path of megalomania, followed by embarrassment, humility, and discovery of its role as moral, not civil, authority. Unfortunately, there are far more destructive weapons to use in its bloody years than the cannon available to our Christian forebearers.