Even the word "lavatory" comes from a Latin word that means "to wash." While it's always a good idea to wash up after visiting, say, an airplane lavatory, everyone knows that's not really why people form lines outside those tiny cabins in the sky.
It gets even wackier at sea. Sailors use the phrase "poop deck" without blushing. But that's because they're not using it for the advertised activity. The "poop" comes from the Latin word "puppis," which means stern.
For landlubbers, the stern is the rear end of the boat--something that does nothing to relieve the confusion about the purpose of the poop deck. Meanwhile, the "head" is where you go to the bathroom, possibly because the head of the boat is the safer place to seek such relief, due to the direction wind blows.
And frankly, even the word "toilet" is a euphemism. It comes from the French word "toilette," which meant "bag for clothing." As if!
All this aside, there is good reason for us all to be less bashful and more worshipful when it comes to the toilet. We may live in an age of computerized potties that can clean themselves, but this might not always be the case. Once upon a time, Crete was a world leader in lavatories. Now, it's just best to say they still produce great olives, yogurt, and honey, and leave it at that.
Maybe had the Cretans kept a better handle on their history, their contribution to the world wouldn't have been lost in the sewers of time.