Absolutely true, and also why I'm not a humanist. Even if I were an atheist, I would reject utopianist nonsense.
Do you think perhaps the Utopian fantasy is some kind of innate longing for a return to Eden? I mean, a Utopia without God IS impossible just as the idea that humans are capable of creating such a thing knowing the propensity we have naturally towards depravity. If we could ever create such a place, it wouldn't take long for the worst among us to destroy it.