The fields that users can select from on their Privacy settings is controlled by their access to these fields. If a field is hidden from them under Core > Settings > Profile > Profile Fields, the users will not be able to modify it. This includes when viewing it as a Platform Manager. To update the user's privacy settings, either set the  Profile Publish Access for ALL Users, or allow access to view the fields by:
  1. Go to Core > Settings > Profile.
  2. Select Profile Fields.
  3. Select the role to modify from the drop-down.
  4. Click Edit.
  5. Mark either View or Edit for the fields in question.
  6. Click Save.
  7. Repeat steps 3-6 for any additional role(s) that need to be modified.