they don't give a shit, it is the only reasonable explanation
they already understand everything about us and probably better than ourselves, if they wanted something from us they'd have taken it by now, if they didn't want us to exist, we wouldn't, they could kill us all in an instant with a swarm of undetectable nanomachines that deliver neurotoxins or something, we'd all drop dead like sacks of potatoes, our civilization would erode, herds of feral cattle would graze in our parks as they migrate across the plains, gradually evolving back into aurochs, only knowing it as an unusually rocky area