Primal will always be public. There is not any way for you to post a note to a public relay and specify that X people aren't permitted to view or interact with it. If it's on a public relay, it's public, and Primal only has their public caching relay for people to read from. They don't seem to be interested in allowing folks to have separate private relays they can read from and write to. Not only that, but how would access be restricted on that relay based on your preferences? Relay access restrictions are global to all users on that relay.
So nostr:nprofile1qqs9xtvrphl7p8qnua0gk9zusft33lqjkqqr7cwkr6g8wusu0lle8jcq9vhrm will always be public and there is nothing they can do about it. Nothing? Nostr may have its intentions but there are can measures in place as a workaround to accommodate a different user experience. Technically the world is a public place but we still use doors, locks, curtains, etc.