Atheists, tell me, a Roman Catholic: why should I become an atheist?

[Tonus]

Our species makes up these artificial clubs as a way of creating social order to make excuses as to getting at resources.

As a social species, it's natural for us to form closed groups and use all kinds of mental biases to inflate the importance and value of our own group versus any other. Religion is a pretty sophisticated way of doing that, in that it involves the creation of the ultimate alpha male that the group follows even if they cannot interact with him in any way. It's also a very ugly way of doing that, in that it makes it much easier to excuse --and even encourage-- the worst kinds of behavior. Yahweh of the OT doesn't even pretend that he's offering peace to the world; he bloodies his knuckles and goads his followers into massacring groups of people and sometimes even their livestock. There is nothing necessary about what he does. It's pure bloodlust.

Evolution is an imperfect system that often involves conflict between species and even within a species. Not the most ideal way to promote the continued survival of any particular species, as evidenced by the high rates of extinction that life on Earth experiences. A perfect system would involve a high level of cooperation both within a species and between all species so that the efforts to maintain balance did not require as much violent aggression and killing as our planet experiences. Our world doesn't point to the existence of God. Heck, neither do our gods.