One can only call to mind the Marxists who ran the Soviet Union.
While Michael Moore trashes capitalism and advocates Marxist socialism (the ideology of the bread line and the gulag camp) - he doesn't put his ideology where his wallet is. The man lives like a Persian potentate and has nine homes. He acquired this vast wealth and lives this elite mega-rich lifestyle not thanks to socialism, but thanks to capitalism. He produces things (films) that people are willing to pay for, and the freedom to profit, that is, to reap the rewards of these voluntary exchanges, allows him to make more money than hundreds of workers will ever see in a lifetime. The right to own private property - the very basis of capitalism and the antithesis of Marxism - means that he is free to buy as many houses with his rightfully-earned money as he chooses. He could never have lived like this in the Soviet Union, unless, of course, he were a high-ranking member of the state apparatus.
Moreover, Moore is just plain wrong about Christianity endorsing Marxism.
Christians are to give alms (Matt 6:1-4) out of the kindness of their hearts (2 Cor 9:7) - in other words, voluntarily. Marxism thrives on compulsion, fear, threats, intimidation, and state power to seize property, to imprison, to stifle dissent, and to kill. Marxism demands complete loyalty and obedience to the state over and against religious belief. By contrast, Christianity recognizes private property (Ex 20:15) and the need to work in order to eat (2 Thess 3:10), not to mention the right of a property owner to pay his workers as he chooses (Matt 20:1-16).
The good news is that Michael Moore doesn't actually work for the state, and thus can't put anyone against a wall and shoot them in the name of "the common good." Hopefully, he'll be content to continue to enjoy his nine homes in hypocritical dissonance with what he claims to believe - and just leave the rest of us alone to enjoy the fruits of our own labor as he does.
But as George Orwell's Animal Farm powerfully pointed out, in Marxism, some animals are always more equal than others, and Marxist ideology is always filled with exceptions for the pigs who out-compete the other animals to elite status on the farm.