I think you might have got muddled up with the template.
If you're trying to override the view for the front-end of your website, you need to copy the view files to the front-end template. By default, it will be Protostar, not Isis
You have 5 different views with the com_users
component:
- Login
- Profile
- Registration
- Remind
- Reset
So if you want to override the Login view, you need to copy the PHP files from here:
components\com_users\views\login\tmpl
and your end result will be:
templates/MY_TEMPLATE/html/com_users/login/default.php
templates/MY_TEMPLATE/html/com_users/login/default_logout.php
templates/MY_TEMPLATE/html/com_users/login/default_login.php
Hope this helps