Kobe wrote:What a religion theoretically teaches and what it's followers practice are two different things
If I am reading you right and you mean to say that in actual belief there is no religion which doesn't fancy itself as the "only way", there are indeed many such religions that do so in theory and practice.
and it has killed a lot of people.
Meh, I don't get this argument. Religion hasn't killed people, wars have killed people caused by various socio-economical and political reasons. Religion was merely a motivator, a propaganda tool for the men going to war, something else would had been used if not religion, just like how freedom and democracy has killed lots of people in middle east.
if there is a religion that posits it is not the only way, then it should have no problem with lack of adherence to the faith. Either way there is no real reason for an atheist to learn more about it.
Why shouldn't atheist learn about religions?
I am an atheist but still fascinated by religions, why be ignorant, is this now we should be preaching, ignorance?
Of course atheists also should learn about religious beliefs and practices if nothing then just out of curiosity.