But for a perfectly nice normal person who isn't some kind of sociopath to do something truly evil.... that takes religion.
See that is a great point. If you were going to write a book or something about this subject, that is what I would recommend you use as your thesis. I think I have a better understanding of what you are saying then when you simply said "all conflict today is caused by religion." I would still add that any kind of strong ideology combined with indoctrination could also someone to do something evil.
You're right on all points there. I should know better than to use a blanket statement. There are nearly always exceptions, so blanket statements will be silly 99% of time. There are lots of examples that prove any strong ideology with indoctrination and/or brainwashing works the same way.
Communism and Nazism are 2 good examples. In fact some people define them loosely as a religion, because people believe in them with the same kind of fanatical unquestioning devotion as a spiritual religion.
As a matter of fact I lump those people into the same category. The reasons being:
They have their own supreme texts
They bow to a leader in a way like worship
They are taught to never question
They are indoctrinated and brainwashed
They want to bend others to their will
Ancient Rome and pre-1945 Japan are 2 more examples. Fascism in general is another example (including racial purists).
Look at China's brutal treatment of Tibetans. It very much resembles a holy war like the crusades.
In fact if you are familiar with Richard Dawkins concept of memes being like a social version of genes, you can see how these ideologies are like the social version of viruses. They spread, replicate and are self defensive. So a recent point Professor Dawkins made is that these ideologies are to viruses as memes are to genes.
A very interesting subject for sure.