Out of all the facilities and utilities these ponies could invent for the convenience of their everyday lives, the ones they made are designed to be used by humans for some reason. How did that happen? Are they even aware that these things they're using are for humans? Do they even know what a human being is?
It is a conspiracy. Humans inhabited equestria along with the ponies but discord destroyed the species (at least equestria's population anyway) and the ponies decided to adopt the humans old tools and devices. Celestia had to cover it up due to some weird political stuff. Then Lyra began to unravel the conspiracy and the ihumanati began chasing her to stop her but... uhm... YOU HEARD NOTHING!!