Re: It's not agressive atheist - it is an agresive theocracy
Quote - "ALL communist regimes have been aggressively anti-religion."
Almost correct. That is because they had an existing religion integrated into the state already so they were aggressively anti-other-religions.
A lot of people in this thread quote the cult of personality as an example of the religion. It is not quite correct - it is the theocratic artefact of religion in the ex-Soviet States. The religion itself was what the Soviet States referred to as "communism". It was a state religion same as in ancient Egypt and other theocracies. Anyone questioning it and not believing it was dealt with swiftly once and for all.
The Manifest is a wonderful piece of Utopia, but fundamentally there is nothing wrong with it. Das Kapital builds on it and while its first part makes sense, towards the 3rd it its total drivel, bollocks and unjustified conjectures. Lenin's scribblings on top of that are complete and utter bollocks (and uncomprehensible towards the end which is normal for someone with 3rd stage syphilis). I am not going to even characterise the "development" of these during the 70 years of soviet rules by paid philosophers. The only way to accept all of these as a fundament to society was to believe (usually in a very simplified "layman" form). Nobody in his sane mind would have accepted these rationally and logically.
So rather unsurprisingly, 90%+ of signage, posters, slogans, etc in the ex-Soviet block were about belief or belief based. We believe in the Bright Future under Communism. We believe in the victory of the people. We believe... believe... believe... period. Whoever does not believe, the holy inquisition will deal with him (insert appropriate local name for it here).
The personality cult was just a topup on that - the pharaon as a manifestation of the single state religion merged into the state in a theocracy. They were not the religion per se. The religion was "communism" (quotes intended as it has nothing to do with what Marx and Engels wrote in the Manifest). This religion treated all other religions the way all state religions usually do.