...................Atheism

 This occurred because an overriding principle of atheistic communism is that the ends justify the means. If there is no God, and humans evolved from algae, then "survival of the fittest" logically becomes the standard for people's behavior. You can then justify stepping on people, killing people, and using any means to achieve your ends. This is precisely what the communists did. They used the means of killing, lying, spying, intimidation and war, to try to achieve their end - the atheistic communist utopia.

 The official journal of the Soviet Academy of Pedagogical Sciences published a government directive, Atheistic Education in the School, as a resource on how to separate God from human society. The opening paragraph is revealing:"The Soviet school, as an instrument for the Communist education of the rising generation, can, as a matter of principle, take up no other attitude towards religion than one of irreconcilable opposition; for Communist education has as its philosophical basis Marxism, and Marxism is irreconcilably hostile to religion.‘Marxism is materialism,' says V. I. Lenin; ‘as such, it is as relentlessly hostile to religion as the materialism of the Encyclopedaists of the eighteenth century or the materialism of Feuerbach.'" Another excerpt reads:"‘Religion'," Marx said,"is nourished not on heaven but on earth, and with the annihilation of that perverted reality, of which capitalism is the theory, religion will perish of its own accord.'"

 (from http://www.topix.net/forum/topstories/T7FI8BPIBPCE4HSUD)

In the following quote, the communist leader V.I. Lenin admonishes communists to be more diligent to translate and distribute older atheistic writings to help with the advancement of atheism in the Soviet Union:

 V. I. Lenin:
Engels long ago advised the contemporary leaders of the proletariat to
translate the militant atheist literature of the late eighteenth century
for mass distribution among the people. We have not done this up to the
present (1922), to our shame be it said (this is one of the numerous proofs that
it is much easier to seize power in a revolutionary epoch than to know how
to use this power properly). Our apathy, inactivity and incompetence are
sometimes excused on all sorts of "lofty" grounds, as, for example, that
the old atheist literature of the eighteenth century is antiquated,
unscientific, naive, etc. There is nothing worse than such
pseudo-scientific sophistry, which serves as a screen either for pedantry
or for a complete misunderstanding of Marxism. There is, of course, much
that is unscientific and naive in the atheist writings of the
eighteenth-century revolutionaries. But nobody prevents the publishers of
these writings from abridging them and providing them with brief
postscripts pointing out the progress made by mankind in the scientific
criticism of religions since the end of the eighteenth century, mentioning
the latest writings on the subject, and so forth. It would be the biggest
and most grievous mistake a Marxist could make to think that the millions
of the people (especially the peasants and artisans), who have been
condemned by all modern society to darkness, ignorance and superstitions -
can extricate themselves from this darkness only along the straight line of
a purely Marxist education. These masses should be supplied with the most
varied atheist propaganda material, they should be made familiar with facts
from the most diverse spheres of life, they should be approached in every
possible way, so as to interest them, rouse them from their religious
torpor, stir them from the most varied angles and by the most varied
methods, and so forth.

The keen, vivacious and talented writings of the old eighteenth-century
atheists wittily and openly attacked the prevailing clericalism and will
very often prove a thousand times more suitable for arousing people from
their religious torpor than the dull and dry paraphrases of Marxism, almost
completely unillustrated by skillfully selected facts, which predominate in
our literature and which (it is no use hiding the fact) frequently distort
Marxism. We have translations of all the major works of Marx and Engels.
There are absolutely no grounds for fearing that the old atheism and old
materialism will remain un-supplemented by the corrections introduced by
Marx and Engels. The most important thing - and it is this that is most
frequently overlooked by those of our Communists who are supposedly
Marxists, but who in fact mutilate Marxism - is to know how to awaken in
the still undeveloped masses an intelligent attitude towards religious
questions and an intelligent criticism of religions.

(full text: http://www.marxists.org/archive/lenin/works/1922/mar/12.htm)