You are absolutely right, however, as ben_w below also pointed out, while the economical / environmental impact might not be justifiable in our western bubble, it might be outside of it.

There are still places on this planet where clean drinking water is a scarcity, and therefore - along multiple other reasons - water-flush toilets and accompanying infrastructure cannot be (easily / justifiably) built.

However, as we can see there are different solutions to the problem itself (health-risk free, humanic way of taking a dump) without using up gallons of water.