As we have often said in the past, Kunena
is not responsible for site registration (see
How do I register new users to my website and where should they login to use my website?
When you register yourself on a Joomla website, unless the site offers you an "unregister" option, you place yourself in the hands of (and at the mercy of) the manager of that site. If you have issues involving your need to unregister yourself at a particular website then you must resolve those matters with the manager of that site. This is not a Kunena
issue nor is it something that we can help you with here. This is a private matter between you as the manager of the site in question.
In resolving issues reported to us, we do not register ourselves at users' websites for the simple reason that, once registered, we cannot unregister ourselves. That's "par for the course"; that's the way that most Joomla sites operate. It's a question of personal security, nothing more. If people are unsure about the registration policy implemented at any