As I stated above, I recently read How Religion Poisons Everything as well. No idea if you've read this book yourself, but it has some very compelling arguments as to the evil nature contained within religion.
Putting faith and believing in the creative works of human beings, using those beliefs to start wars, shun homosexuals, commit acts of horror and atrocity.
And this doesn't just come from "large hierarchies". Have you considered the religious suicide cults of the world? Even on a small scale, group think through the template of religion can be very deadly.
