@rafasalo the answer is the same. It doesnt matter what plan you have. The user must make it publicly visible if you are using gitlab.com. If you have your own server then use a login with admin rights and then you will see it.
Since only the Gitlab team can be admins of gitlab.com then the only way to resolve is run your own server and be an admin or have the users publicly display the email when using gitlab.com. But if you don’t wish other users of gitlab.com to see this then your only solution here is to run your own server.