It doesn't particularly; Karl Marx was an atheist and believed that religion was bad for society, so Marxists are probably atheists - but it certainly isn't true to assume that most atheists are...
Marxism was originally created by philosophers Karl Marx and Fredrich Engels in the Communist Manifesto (brilliantly written, highly suggested) during 1848 in the midst of the first Red Revolution...
Since the general collapse of international communism around the year 1990, there are relatively few countries in the world which practice any form of Marxism or Marxist-Leninism. Cuba and Vietnam...