Why? Because there is no unanimity among atheists on religion. Different atheists believe different things about the value, nature, and future of religion and religious beliefs. Its impossible to ascribe one overarching position about any aspect of religion to all atheists or even most atheists.
The fu. . .?
I'm taking it you posted this solely to get in your required minimum posting number for that online ring vendor you are promoting in your avatar, because the content is ridiculous.
Atheism is the absence of a belief in theism. There are no 'flavours' of absence of theist belief. It is either present as theism or it is absent as atheism.
Agnosticism is just someone who doesn't want to commit to either position.