The issue is too generalized. Religion in my opinion is a delusional system, which encourages grandiosity, bigotry, irrational thinking, and belief that God approves of their ideas.
The danger is that religious belief systems are associated with higher risks of mental illness. Delusional belief that is beneficial to some people may lead the mentally pre-psychotic to violence and murder in the name of their god.
Christianity and Islam span a wide spectrum of beliefs from healthy to psychotic.
Unitarians are at the healthiest end. Seventh Day Adventists are also healthy, as are Quakers, Mennonites, Liberal Anglicans, and Liberal Catholics. Roman Catholics, Mainline Christians and others are in the middle. Southern Baptists are edging toward extremism and bigotry. Christian Reconstruction, Dominionism, Theonomists, Christian Identity, Army of God, the Ku Klux Klan, American Nazis, and Aryan Nations are on the mentally unstable extreme. These are the killers of Abortion doctors, Homosexuals, "uppity blacks", Jews, Atheists, and Liberals.
I personally know Islamic doctors, dentists, nurses, and physical therapists who are great humanitarians, family people, and pro-democracy. They are on the good end of the Islamic spectrum. There are moderate Muslims whom I have met in North Africa despite living in dictatorships. On the crazy end are the Wahabis, Al Qaeda, Taliban, Hezbollah, Hamas, and Muslim Brotherhood.
One cannot group all people of Christian faith in one basket or all Muslims into one basket. The same can be said of those who lack belief such as Atheists. Some atheists are outreaching to believers, tolerant of all views, ranging to hostile atheists like Sam Harris or Richard Dawkins.
We need to recognize that there are bigots, extremists, racists, hate mongers, and psychopathic killers in all groups. One does not group all psychopathic killers into broad diverse groups like Christians, Muslims, and Atheists.
Kasavubu