I am travelling out West right now in Wyoming and Montana.

Yesterday, I went to two restaurants in Wyoming. Both had a restroom for ladies and men. However, each was an identical single toilet (no urinal) and a locking door. They were designed to be used by one person at a time.

Why not just mark each of the two restrooms as "Restroom" instead of a gender specified on each?

It doesn't really make sense, does it, for single toilet restrooms to be one marked for "men" and one for "ladies"?