The articles from https://confluence.atlassian.com/servicedeskcloud/serving-customers-with-a-knowledge-base-732528995.html is misleading users , and there are not sufficient guide/steps on configuring this. As this will need further configuration on Confluence side to ensure that the functionality "Allow all active service desk users and customers" to works properly. This has lead to creation of bug ticket created in JAC due to the confusion that occurs:
https://jira.atlassian.com/browse/JSD-3448

If you choose to restrict viewing of the linked Confluence space to licensed users, you must grant customers a Confluence license or open your Confluence space to anonymous access.

Which I have broken down to below:

If you choose to restrict viewing of the linked Confluence space to licensed users, you must grant customers a Confluence license (this is correct)
If you choose to restrict viewing of the linked Confluence space to licensed users, you must open your Confluence space to anonymous access ( this is not correct, why would you want to open Confluence space to anonymous access if you would like to restrict it?)