Look, anyone using YouTube or myriad other "social media" apps should know that all content defaults to Public unless otherwise specified, and even then, should be assumed public because, what even is the point of "privacy" when you're uploading stuff to social media?
Whenever I create a playlist, YouTube makes it Public until I dropdown to make it Unlisted or Private. All your settings are just gonna keep defaulting to Public and you're gonna need to micromanage everything, unless you simply give in and let it all be Public.
So it's not really a bug as described, just a feature. Let's just face up to the fact that social media is public.
Remember in the old days when they said "don't write anything in email you wouldn't want to see in the newspaper"? Well, extend that to social media [including YouTube and creators], and now we've got an idea of our false sense of privacy.