atheists

To be fair, there are atheists in this world that try to convert people to the path of atheism. But, you're right in that they are rare. The reason is because Atheists don't typically see a problem with someone who believes in something different then themselves. They may pity them, or think they are "delusional", but they don't actually have a problem with someone believing in whatever it is they want to believe in. Monotheistic religions, on the other hand, are typically taught that anyone who doesn't believe what they believe will go to hell. Because they are taught that hell is a horrible place, and they are also taught that they should love everyone, they feel it is their place to convert unbelievers. They believe that, by converting those who do not believe as they do, they will either directly or indirectly be responsible for saving someone from an eternity in hell. They believe that they will save their soul, basically.

Atheists usually don't care what other people believe or just aren't involved and feel that everybody has the right to their choice. Trying to convert an atheist is both unfair to them and like trying to break down a brick wall with a feather duster. People choose atheism for many reasons. I've never had one try to convince me that there was no god.