The first rule of 8 Garudhammas

So according to the 8 Garudhammas of Bhikkunis this is the first one. > 1) A nun who has been ordained even for a hundred years must greet respectfully, rise up from her seat, salute with joined palms, do proper homage to a monk ordained but that day. For me this sort of pushes the males to superiority. What is the reason for this? Is it accurate? Where can I find a reference to it in the Vinaya Pitakaya?