Yeah but they worship their leaders, just look to NK where the commies go bow and worship the statues of Kim Jong-il and Kim Il-Sung.

So it's actually a religion.
Do you remember the Mausoleums the Soviet Union had where the little commies went to see the corpses of their leaders pay homage to those scumbags etc.

Communism is more religion than people think, only missing thing is God, they got the rest. The got books and manifestos, leaders, propagandists (priests), inquisitors etc.

They even have a faith component, their belief in the unproven evolutionary fairytale.