Shuai,

Why don't you first define your understanding of communism and atheism and then ask the question. I really don't get your version of communism and atheism.

 

As I see:

 

Communism: Is socio-political. Got nothing to do with religion. Some communist leaders insisted on adding 'no religion' rule fearing that religion will go against their ideology. This doesn't mean atheism will go with their ideology.

 

Atheism: Is spiritual. Not believing in a supreme being - God. Atheism has nothing to do with equality etc. 

 

"Life is like a bicycle, if it's too easy - you're probably going down :)"