Don't panic when you see your private environments on your public documentation. This is visible to only you because you're logged into your account but it's not visible to any other person accessing the public URL. If you log out account from your account and try accessing the link, you won't see your private environments.
In the image below, the "testEnv" is assumed to be a private environment for the user and shouldn't be public but because this user is logged in to their account, this environment will be accessible to them.
We are working on a better view for users so that they know about this scenario and don't get worried about their private data.