Kurt Vonnegut talked in his speeches about the fact that Karl Marx called religion "the opiate of the masses." Vonnegut explained that when Marx wrote those words, opiates were the only options that a lot of people had to deal with illness. Some people abused opiates, but opiates also allowed some people to function despite debilitating pain. So, Vonnegut contends, Marx wasn't saying that religion was a bad thing, he was saying that religion is like medicine for people who are oppressed and suffering. Religion did not cure the problem of oppression, but it helped oppressed people cope with their suffering.
Think of all the damage done, all the rights crushed, over a mistranslation. Not that the communist regimes that oppress religious folks are otherwise the fuzzy, permissive sort.