Probably fairly peaceful, intelligence or weirdness aren't at play here. The dangerous ones are those who deal in the practical realities of the world in ways that can effect change - they are more likely to have the means to do something. Engineers and chemists are ones to watch (whoever did the script for Breaking Bad knew his chemist stereotypes).
In my mind, the common threads with organize terrorism is utilitarianism and consequentialism. This way of thinking has a big overlap with stem fields based in logic and physics.
The perhaps concerning thread socially is the rise of utilitarian and consequentialist morality.
