That is too simplistic. This happens to ALL WP websites that utilise user registration – regardless of what plugins they have installed.
I don’t really understand the issue. WordPress offers you – on that admin panel – a list of the registered users. That is what you are seeing. It is called ‘All Users’.
And, as stated – you have filters at the top so you can look at only users from specific WP roles if you prefer to look at the list in that way.
