Scientific studies have shown that most people are guided not by rational thought but mostly with things like: instinct, emotions, and other internal desires. This conflicts greatly with the enlightend belief that most of us atheists/rational/left wing people have. When we try to reason rationally with people about all kinds of philosophical matters, the regular people usually resort to their beliefs without giving arguments a fair chance.

This is not only the case when we reason against the existence of God. But also when its about any other matters. They cling emotionally to their beliefs because without it their world view falls apart. But still its important to try to do so. If we didnt shatter world views before, we would still believe in the Ptolemaic earth-centric galaxy view. Its our task to shatter those paradigmatic views. I believe such a view also exists when people consider ideologies like Socialism, or historical figures like Stalin. Instead of studying primary sources, people rely on hearsay, indirect sources, memoirs, testimonies from enemies of Socialism etc. Historians and interested people should detach themselves before studying such issues. The Cold War tainted the historical studies about Stalin and the USSR in such a way that it became warped from reality. My personal opinion is that Stalin was not even a dictator and that the USSR was a complex form of proletarian democracy that got sabotaged from within.

As Marxists we must find the material truth behind any terminology, historical event and such.

For example, a highly misused word is "Freedom". Freedom by itself has a noble meaning but it also has a class character. Technically in Capitalism we are free yes: to be exploited, to be frustrated and to vote now and then for some bourgeoisie politicians not bothering with mass-opinion.
While we as working class want "real" freedom. That means that we want political and economical say in matters. We want to be in control of both. We want to be "free" from exploitation and we want to be "free" from a ruling class dictating and controling every part of our lives. This is the class character of our "freedom".

The bourgeoisie has the freedom in their hands now in most countries. They have the "freedom" to exploit, control and dictate things to us. They have the "freedom" to send the police or army against us when we get organised. When is the time of "our" freedom?

This capitalist system is such an abomination against human nature, that it doesnt permit people to have their own thoughts. It controls them in every single way, and it controls all feeds of informations, from newspapers to tv stations, and with this control of the peoples minds, people become mere parrots of the official pro bourgeoisie, pro capitalist thoughts. And after it does all this, the system and media claim that people have the freedom of thought and speech, while it doesnt let them think for themselves in a rational way!

For example: Lenin puts it in the following way:

"People always have been the foolish victims of deception and self-deception in politics, and they always will be until they have learnt to seek out the interests of some class or other behind all moral, religious, political and social phrases, declarations and promises."

Lenin, The Three Sources and Three Component Parts of Marxism (1913)

Karl Marx on the differences between a private property orientated society and a communist society and its division of labour:

"As soon as the distribution of labour comes into being, each man has a particular, exclusive sphere of activity, which is forced upon him and from which he cannot escape. He is a hunter, a fisherman, a herdsman, or a critical critic, and must remain so if he does not want to lose his means of livelihood; while in communist society, where nobody has one exclusive sphere of activity but each can become accomplished in any branch he wishes, society regulates the general production and thus makes it possible for me to do one thing today and another tomorrow, to hunt in the morning, fish in the afternoon, rear cattle in the evening, criticise after dinner, just as I have a mind, without ever becoming hunter, fisherman, herdsman or critic. This fixation of social activity, this consolidation of what we ourselves produce into an objective power above us, growing out of our control, thwarting our expectations, bringing to naught our calculations, is one of the chief factors in historical development up till now."

Karl Marx. The German Ideology. 1845 Part I: Feuerbach. Opposition of the Materialist and Idealist Outlook: A. Idealism and Materialism, Private Property and Communism.

"To belittle the socialist ideology in any way, to turn aside from it in the slightest degree means to strengthen bourgeois ideology. There is much talk of spontaneity. But the spontaneous development of the working-class movement leads to its subordination to bourgeois ideology; for the spontaneous working-class movement is trade-unionism, and trade unionism means the ideological enslavement of the workers by the bourgeoisie. Hence, our task, the task of Social-Democracy, is to combat spontaneity, to divert the working-class movement from this spontaneous, trade-unionist striving to come under the wing of the bourgeoisie, and to bring it under the wing of revolutionary Social Democracy."

Lenin, What Is To Be Done?, The Spontaneity of the Masses and the Consciousness of the Social-Democrats (1901)

And this is a clearcut message to all the idealistic type socialists and communists, the Trotskites and the anarchists and what else. To become a Marxist doesn't just mean to become a revolutionary, it also means becoming a scientist in the most rational and scientific of ways.. to become a philosofical dialectical materialist. According to Lenin you have to follow these principles and basic assertions:

1) Things exist independently of our consciousness, independently of our perceptions, outside of us, for it is beyond doubt that alizarin existed in coal tar yesterday and it is equally beyond doubt that yesterday we knew nothing of the existence of this alizarin and received no sensations from it.
2) There is definitely no difference in principle between the phenomenon and the thing-in-itself, and there can be no such difference. The only difference is between what is known and what is not yet known. And philosophical inventions of specific boundaries between the one and the other, inventions to the effect that the thing-in-itself is beyond phenomena (Kant), or that we can and must fence ourselves off by some philosophical partition from the problem of a world which in one part or another is still unknown but which exists outside us (Hume)—all this is the sheerest nonsense, Schrulle, crotchet, invention.
3) In the theory of knowledge, as in every other branch of science, we must think dialectically, that is, we must not regard our knowledge as ready-made and unalterable, but must determine how knowledge emerges from ignorance, how incomplete, inexact knowledge becomes more complete and more exact.

Lenin, Materialism and Empirio-Criticism (1908)