I would say "The locker rooms are not private" for a more natural translation. But it's unclear what the philosophy on this course is: I tend to stick with the unnatural translations first since more natural improvements are rarely accepted. On the other hand, there are other sentences which expect very specific translations into a particular English idiom.
So, unlike every other Duolingo course I've done, this one requires rather more adaptation to a sort of broken English.
Don't get me wrong: I appreciate the course being here and I recognize how hard it is to try to cover all the possible ways of expressing a translation. I've just gotten rather spoiled by how comprehensive the system is in some of the more popular languages on here, so it's rather grating sometimes to have to do these occasionally nonsensical English "translations" to proceed.