As stated in the directions, setting the password policy the default, which is Yes causes the front page to become hidden until a visitor logs in to Moodle. When visitors first hit your Moodle site, they see the Moodle login page.
Setting this to Yes means that you cannot use Moodle's front page as an information and sales tool. You can customize the text on the login page, but you won't be able to add all the features available on the front page.