The answer: Religious faith is evil. It is the greatest cause of harm this world has ever known.
the problem with your logic is that you are associating the actions of a few with the actions of all, or rather, that if one person is like this, then all are.
faith is neither inherently evil or good. it just is. it is what the people do with their faith. some choose to blow others up. others, like mother teresa, choose to help people.
so not only has faith been the source of many of the world's problems, it has been the source of many of mankind's attempts at humanity, at charity, and at being a good person, overall.
some say science is evil. why? the a-bomb. but, like faith, science is neither evil nor good. it is what the people do with it. science has helped us eradicate (at least for now) several diseases, such as smallpox, or the now unheard of polio (in the US). In the wrong hands, it leads to death and destruction, such as with Saddam's chemical warfare against the Kurds, or Hitler's systematic (attempted) destruction of the jewish people.
is science evil, then? it's killed more people in this century alone (well, the last one technically, I'm still stuck in thinking that this century is still the 1900s). I think the number is around 100 million. more people than have been killed by war in human history (most of which wars were started because of religion and faith).
the answer is, as I've pointed out several times is this. Faith (or science) are neither inherently evil or good. the important thing to remember is what the people, the PEOPLE, did with their faith (or science). Faith and science only become evil when used incorrectly by people, and only become good when used correctly by people. so it is the action, not the philosphy that is inherently evil or good.
I know this was briefly touched on by nwr, and I also realize that this is off topic, and that this thread, or this portion of it at any rate, is old. so if anyone else covered this, well, it's always good to have a refresher.
All a man's knowledge comes from his experiences