I'm saying, eradicate religion and these people are going to kill for some other cause. Religion is being paraded around as their current justification but the people are responsible. Take away religion and do you think extremists are suddenly going to become moderate, law abiding citizens? The answer is obviously no. With or without religion, the people choosing to kill will always have a reason to do so.
You don't really know that. I can understand the stereotype of the power hungry leader with personal interests who uses his prominence to manipulate others and achieve his goals, or the random psycho, filled with hatred, that finds in it a platform for violence. I admit these, or analogous sorts, might represent a fair share of people involved in religious violence, and that many of them could find other escapades that would end with equally upsetting results.
Thing is, I think religion contributes to violence in more subtle and widespread means. Mainly by leading to intolerance, inhibiting critical thinking, by promoting rigid frameworks of thought where concepts like punishment and judgement abound, etc. I think it delays humanity progress. I'm talking about organized religions as institutions, obviously. The magnitude of this impact varies, of course, through time and location.
Also, even when you consider that it only provides a "justification", a justification or sense of righteousness may very well be the difference between acting or not acting in plenty of circumstances.
To some degrees it can even be just self-inflicted, or just psychological. But it's negative nonetheless. Having been born in a deeply catholic place and having been subject to all kinds of attempts at indoctrination by family members and community, I have a very vivid memory of my childhood as a catholic. I'm fully aware of the difference of going to bed feeling guilty, resentful, or afraid, due to some completely unjustified bullshit that would have no bearing in my life if I had just been educated in a "normal" way. I'm glad I got over it spontaneously and very young, and sometimes I dread what would become of me if that hadn't happen to me. All I know is that I was a lot more free and a lot more tranquil when I stopped believing. Fortunately this was all in a very "mild" environment, but I can only imagine in more fanatic mediums it being much worse.
And it provides a seeding ground for much worse things, that may or may not happen. We sit here and we all agree that things like ISIS caters to disenfranchised youth in Europe for example, and look how many thousands of those have joined them. Now try to picture the world without religion, and try to imagine something with a similar impact. I can't really think of anything that would lead to such an enormous amount of people joining a bloody and sadistic war at a whim. Would they travel to some far away country, completely unrelated to them, to fight for a political cause? Or to Mexico to join the cartels? I really doubt it, I can't think of a phenomenon that ticks these boxes so randomly as religion does.
I'm also drunk. So I apologize if anything is confusing.