Atheism's answer isn't communism, for one thing.
Totalitarian communist regimes suppress religion because of one person: Karl Marx. You know the famous "opium of the masses" quote? Here's more of it:
"Religion is the sigh of the oppressed creature, the heart of a heartless world, and the soul of soulless conditions. It is the opium of the people. The abolition of religion as the illusory happiness of the people is the demand for their real happiness. To call on them to give up their illusions about their condition is to call on them to give up a condition that requires illusions. The criticism of religion is, therefore, in embryo, the criticism of that vale of tears of which religion is the halo."
In other words, according to Marx, oppressed people use religion to make their oppression bearable. If you remove their religion they will truly feel the suffering of their situation, and be spurred to rise up and revolt. Once socialism is in place and the people are no longer oppressed, they will no longer need religion.
Communist dictatorships have of course done little to alleviate the suffering of the people living in them. They see the persistence of religion as an outward sign of this, and thus pretending that the populace is happily irreligious by forcibly ousting religion becomes an ongoing requirement for international PR.
Marx may or may not be right about religion, but he could have told the Communists that forcing people to change, hide or cease their religious activities has little effect on their actual beliefs. (Incidentally, compare the terrible coercion by Communists to the peaceful activism which is now frivolously labeled "militant atheism". Compare that to "militant Islam" while you're at it.)
Communism's self-declared incompatibility with religion does not imply that atheism is responsible for the atrocities committed in the name of communism, even less than anti-Semitic atrocities can be laid at the feet of Christianity. This is because there are no atheistic commandments, no creed, no dogma, no central authority and certainly no "apostles". Nowhere does it say, "There are no gods, therefore do this and this." Communism declares that there are no gods while separately giving its followers commands, but does not link the two.
Atheism is a simple position on the existence of gods, a single conclusion and nothing more. It does not presume to contain answers to today's or any other era's problems. By precluding absolute trust in religious doctrine, however, it leaves one open to secular philosophies and moral systems, which provide earthly, tangible, verifiable rationales for their guidance. Those only interested in "power, wealth and materialistic pleasure" are not following these philosophies any more than they're following Christian morality.
On another topic, to Ruse's list of five "blots" on Christianity I would add three more:
- The continuing attacks on science and scientists in the interest of preserving the plausibility of Christian dogma, from Galileo to Darwin.
- The Thirty Years' War of the 17th century, fought between Christians with the singular goal of spreading people's own idea of God's Word.
- The continuing death of thousands in the Third and First Worlds as a result of intrinsically ineffective abstinence-only education and the defamation of condom use.
Firstly, congratulations on your newfound independence and on increasing your self-knowledge. It can sometimes take a reprieve from the constant background noise of belief to even imagine an alternative to it, even if it's already your position deep down.
You seem to have a good grasp of your situation. I don't know what religion your family adheres to (from the Revelation reference I presume it's some kind of Christianity) or how devout they all are, but the sudden revelation of an atheist in their midst (especially for the first time) will doubtless provoke strong reactions.
It will indeed occur to them that you think they've wasted a lot of effort over the years. It works both ways, too; they'll think you're wasting the effort you've put in all your life. All that work to save your soul, and you're just throwing it away. The important thing is to emphasise that it is nothing personal. Your problem is with the beliefs themselves, not your family. Rejecting the beliefs does not invalidate everything you and your family have done with their church - the socialising, the charity work, the philosophical discussions. Conversely, though, the work they have done does not by itself make the objects of their faith (God, a resurrected Jesus) real.
Your parents in particular may feel they have somehow failed you, and God, by bringing you up to be the kind of person who could reject God. It's not their fault, because all they did was bring you up to think about what you are told and examine things on their merits. This prevents you from living in blind faith, and if you continue to believe you are the best kind of believer: one equipped to defend the faith. There was always the possibility that you would come to the opposite conclusion, and that's the risk. They might find this idea reassuring.
There's one thing I really need to warn you about. Your family may be intelligent, but I get the impression that they aren't terribly familiar with non-belief. They will feel a tremendous urge to try their hand at apologetics to bring you back around.
You expect this, but here's the thing: most of them will not be very good at it. You'll get the most facile, intrinsically flawed arguments in existence thrown at you as if they're irrefutable. They do seem that way to them, because they've accepted them without really trying to test them. Your very delicate task will be to respond to each one as simply and patiently as you can without getting frustrated.
I invite anyone reading this to share their own experiences of coming out to their friends and families as an atheist. It can be every bit as bad as coming out as a homosexual, so some mutual support is always welcome.