You should start with the definition, not with examples with questionable relatedness at most.

Atheist - a person that does not believe in the existence of a theistic god.

It's not an ideology, it's not a lifestyle, it's not even a political conviction. So everything you've written after the colon is basically irrelevant.

But if you are looking for correlations between the single trait of atheism among the human population, you'll find educatedness much higher on the list than murderousness. That's of course, if you value real data and facts.