In the animatrix, we learn that the machines founded a machine-sity state called "zero-one" after finding that coexisting along humans in the human-led nation-states would be impossible. Zero-one subsequently flourishes and its powerful export-economy cripples the economies of the human nation-states. I do understand the latter part: human capitalists being tempted or even compelled to import from zero-one to pursue profit maximization makes sense (However, another good question would be why the machines choose for this economic relation: do they need specific resources that cannot be found near zero-one and thus are compelled to trade?). The current China vs. West relationship is also demonstrative in this regard: close economic links due to cheap imports being possible from China as opposed to political hostility.
My main question is however how the humans could have allowed such a de facto machine nation-state to get into existence: the context in the animatrix is one where the humans are already extremely suspicious of their mechanic brothers, they would surely freak out at the first sign of an independent political entity and quell it at its inception? (something that seems plausible to do)
To anticipate the naysayers: I wouldn't say that this question is a duplicate of this one since that question is more about the weapons used against zero-one instead of the timing. I don't get an answer to my question from the answers given there.