There are a number of past discussions detailing various ways to handle the fact that WD won’t let the end user set the main Public Share to Private. Its been requested long ago in the Cloud Ideas subforum to enable setting the Public Share to Private but its been ignored by WD.
http://wdstagingsplit.staged-by-discourse.com/t/removing-public-share-wd-mycloud/137086
http://wdstagingsplit.staged-by-discourse.com/t/hiding-or-removing-public-share/91932
http://wdstagingsplit.staged-by-discourse.com/t/can-i-delete-or-rename-public-folder/91213
http://wdstagingsplit.staged-by-discourse.com/t/make-it-possibel-to-delete-the-public-share/97047
http://wdstagingsplit.staged-by-discourse.com/t/delete-public-share-folder-or-restrict-access/97081
