Look, I’m 100% with you, I agree, it was likely humans, no question. My point, however, is… it wasn’t brain dead humans, or absurdly unintelligent humans who did it, someone thought about it, planed a scheme to get it done, prepared the site, selected the rocks suitable, obtained the tools necessary to accomplish the task, had a model of what he intended to make, and went about methodically chipping all the rock that didn’t belong in the form he intended to create.
What I’ve just described is intelligence and the process by which all intelligent creations are produced. As such, it stands as a good standard for 1) the identification of what might be or not a product of Intelligence, and 2) one which can be used for this subject we’re discussing; some constructs, like coding, decoding, transmitting, error correcting informational systems, like the Statues defy unguided, non-intelligent sourcing, to even float such a theory is laughably dismissed.