The attacks are not only on Christians, it's the Christians and the rest of the minorities. What motivates these attacks is the fact that they are different and the fact that they consider them as infidels or a person who is different in belief or religion from them. What mostly motivates this as well is partly the agenda of emptying the Middle East of other minorities. Basically, it is to kick them out of the land.
Christian roots in Iraq and Egypt go back way before Islam. Right now we are seeing that people are leaving. The people are forced to leave. The lack of protection we are seeing from the government is really alarming. It is alarming that we are not seeing the government protect them or do anything to support them. In my opinion, the fact that they come from different beliefs and the fact that they want to basically control them is mainly the reason for their persecution.
Also, another important part is that Christianity in Iraq is seen as the American religion and the religion of the west. They consider them as cooperators, or traitors. This is also another element that adds to the reasons for their persecution, because they are Christians like the western religion.