When I was 12, I remember fast track, magnet-program students getting all silly/clever and saying "You know, communism works in *theory*, just not in practice."
I had it pegged for sophistry back then, but I didn't manage to articulate the problem until later: Every philosophy of government or social order works in theory! No system was ever designed to fail, no matter how stupid it looks to us now. "You know, divine monarchy works in theory. I mean, God wouldn't pick some asshole to rule us."
If a system, be it a religion or government, does not function in the real world as it does on paper, then the paper is wrong, not the world.