Violence is only ever used as a proof of power. Therefore if you use violence, you want to prove certain strenghts to your opponent. And conversely, people of true certainty don't use violence.

But fundamentalists seem to be a group whose certainty is evident, but then why would they use violence in their struggle to impose their views on others? And why would they want to impose their views anyway? Is it that their certainty is based purely on the belief, with no proof for it? They childishly say "just because", and are deeply frustrated by not having things done their way. In fact, the fundamentalists — both of the religious and the political kind — are as much unsure and unsecure as they would like not to appear so. Their belief is based on unresolved illogicalities, on unprovable dogmas, on pages upon pages of mysticisms and superstitions. They have resolved to either ignore, or limit opposing views, as they have not a single proof, not a shred of evidence to support theirs. When you believe something that cannot be proved, you can't allow for any spark of doubt, as if there is a reason to believe you're wrong, you probably are. Any proof is better than no proof at all.

But religions were also a tool of social developement when formal education was only available to a handfull of the richest kids, and when the tools of communication more efficient than a loud shout were available only to those who made a nice profit on each message. Now, even the oldest and most widespread of relligions crumble, if for no other reason than their irrelevance to the stage of social evolution we are currently entering.

People who believe in gods are no different from those who believe in astrology, dwarves, and tooth-fairies. Why should I respect that in others what I would certainly not respect in myself? And should I respect a child's fantasy of there being a monster under it's bed, or should I take it as an idication of some emotional problem and help the child get rid of it?

Why do people believe in gods? Everything a living creature does of it's own free will is directed towards raising it's happiness and reducing it's suffering. One way to achieve this is by maximizing one's power over his body and environment. If we assume that there is a power greater than all the others combined, and that influence can be extorted over such power, it is if as one was wielding that power himself.