Priests and children; Osama Bin Laden and the Twin Towers; the Spanish Inquisition, Hitler, Stalin, and so on - these are all obviously terrible and claiming these events or individuals as evidence for the superiority of whichever world view did not happen to take part in the related atrocities is dumb for two obvious reasons. Firstly, individual interpretations of ideas have little bearing on the validity of ideas and secondly, these individual interpretations are generally complex and contradictory which makes it essentially impossible to draw relevant parallels to present approaches to similar questions.
But still, polemicists on all sides of every aisle make a living trying to claim the virtuous for their side and pin those that are evil on others. Any such discussion is boring at best, and misleading at its worst.
I prefer to limit my anti-theistic ramblings, therefore, to things that are necessary qualities of a particular world view. As an argument against a world view, it holds a bit more weight because even adherents are forced to advocate its implications, and furthermore as best as I can tell there are only a few such traits. I find that these two facts simplify the debate, somewhat.
As far as I can tell, every single religion ever conceived has one trait in common: that this physical world is somehow inferior to whatever theistic dimension is described by tha try stem of beliefs. In many traditions this is simply a matter of influence, where the higher dimension simply has authority over ours. Dissatisfaction with this reality doesn't really come into play here just because that other, authoritative dimension is simply inaccessible. Tradition does not indicate that any better options are available. I suppose there is less harm in this, though as science seems to indicate it is inaccurate.
Most of the prominent religions, however, have innovated on this point by adding a path of access. The superior dimension typically retains its authority over ours, but the carrot of a lucky few gaining access to the superior dimension is wagged in the face of us mere mortals.
Of course to convince those lucky few to care enough to dedicate their lives to acheiving whatever specifications are deemed necessary, that superior dimension inevitably takes on some form that increases the intensity of things we enjoy, eliminates things we don't, and frequently invents new things that we wish we could experience. It literally encompasses every imaginable improvement: Are you sick? well guess what, there is no sickness. Are you going to die? Well guess what, there is no death. Are you uncertain? Well guess what, there is absolute knowledge.
I'm trying to define these things as generally as possible to point out commonalities, and to create a picture that is agreeable to everyone. Of course the religiously minded individual would not agree with where I am going here, but more often than not he or she must agree that their religion states the existence of some superior dimension they would like to experience.
And this brings us to the most vile characteristic of religion: it seeds discontent. Everything in this experience is just a little less shiny, and at a young age children are forced to rely on escapism. Rather than take joy in the accomplishments of mankind, they pale in comparison to a hypothetical perfection we have no right to expect. Rather than to preserve and cherish the beauty of our precarious world, they take solace in the existence of a tidy world somewhere beyond that renders the richness around us as ash. Rather than being fascinated by and well prepared for the challenge of discovering a moral compass that functions well in society, the believer is driven towards a dark fear of such uncertainty and a hope for the false safety of edicts.
I'll be the first to admit that this world is confusing, uncertain, unfair and at times uncomfortable. But it is what we have and I'll do everything I can to make the best of it, to do my best within it. By definition, religion does not.