My contention would be that Marxism seeks not so much to do away with religion as to displace it. The idea that one 'may not have any other gods before me' can be seen in the hard-core orthodoxy of any 'good' Marxist; the idea that "God is dead", popularized by Sartre, captured that Nietzschian attitude that we might become our own gods. Similarly, the Christian idea of compassion and self-sacrifice is supplanted by that rhetoric invoking the "New Soviet Man", a figure that resembles in many ways the biblical Samaritan, the "Boxer" of Orwell, the loyal servant to the Party elite. Liberation theology is thus, also, a movement that harkens back to the future - the post-religious roots of socialism invite a call back to that temporal realm, in support of a secularism that rejects the divine itself.
In that socialism is a "Christianity without God", one need only look to the practical application of this paradigm to see in what way this system clashes with the realities of human nature (a failure, incidentally, that all too often can be seen in the historical record of traditionally Judeo-Christian societies as well). The absence of a practical, tangible God creates a vacuum that almost begs to be filled, and there are an overabundance of claimants to that position in any culture. That 'revolutionary fervor' so often invoked by these 'movements' (here, again, a metaphor of change, of advance) invariably leads to dictatorship and tyranny, as the public seeks that entity that might invoke the coming Utopia by a perfected exhibition of the appropriate traits. The Party, the Fuhrer, the People's Will, the dictatorship of the proletariat - all these terms become infused with a quasi-divine authority, allowing their secular priesthood license to commit any sort of crime in their name. In this way, the adherents of these philosophies become the heirs of the Inquisition, in word and deed as much as in form.
In regards to capitalism, one has an easier time of it. Capitalism claims no "New Free-Market Man"; one can only find the American rhetoric of the democratic citizen to rival the power of communist icons. In point of fact, the only symbol of worship is capital, the Almighty Buck (that ridiculous Randian sigil, the golden dollar sign, could only have been borne in the mind of a Neo-Marxist Russian reprobate). The capitalist seeks only profit, desires only to become wealthy and lazy. He acknowledges the crassness of the material, practically revels in it. Jerry Springer could never become popular amongst Marxists. Socialism promises prosperity for all, without the laziness. This is the main failing of the philosophy, of course; that lack of the ultimate bourgeois pursuit is its inevitable Achilles heel. In capitalism, that laziness is also an unkept promise, but the energies such promise invokes allows for a substantially better standard of living for those who live under its spell. For no rich man can sleep soundly in a free-market society, surrounded by competitors and would-be competitors - in these sorts of regimes, it is the corporate CEO that is the hardest worker of all, even as the most talented representative of his peer group. Were it not so, he would soon be replaced, without the benefit of a coup or purge. Capitalism is a self-correcting methodology, and in this lies its strength.
In the secular world, capitalism is king. We must submit to the fact that Mammon rules the secular realm, especially if we give even the slightest regard to the inclinations of the proletariat - not that beast of Marxist mythology, that saintly creature of legend, but the actual article, in the flesh, as he really is. Take away his identity as an accumulator of wealth, and all that remains is tribal affiliations, Rand's "brotherhood", the curse of ethnicity and nepotism and the vicious rivalries they foster.
I think that the answers to the problems of Western society (and, in regards to those in other social systems, ours are positively trivial) can be found amongst the intelligensia, even in the ideas of those lured by Marxism, or by other religious fanatics. There was a pope who said that he might find ideas amongst the Marxists worthy of expousing, yet not be a Marxist. One might bless the troops of Mussolini without embracing fascism - the hope that the Lord might forgive the follies of war can extend even to those practitioners within the camp of "Il Duce". What I would remind those who would tamper with the foundations of Western society is that the foundation of that system is capitalism - and it has proven to be a strong one. Remove that core, strip that society of the engine that makes it, and every industrial society that has ever existed, successful and prosperous, of the mechanism of personal profit and self improvement and self-ordained success, and you crush any hope of 'social improvement' you might optimistically entertain. For when I am separated from responsibility for my own success and livelihood, no welfare state can replace the sense of self-respect that is lost with it. When my ability to purchase freely is made a crime, no wall of laws can stem the inevitable centralization to follow, for some expert of the state shall need to decide in my place what I must have, and what is merely a luxury, and I shall be beholden to him, and he shall be my patron. To ignore that simple fact is to ignore over one hundred years of socialist failure, and to turn a blind eye to the clearly evident nature of the modern welfare systems of the West.
P.S. How's that for an overeducated conservative hack historian? Huh?