Thank goodness for that ! If 22,000 + members posted regularly it would be unmanageable.
Seriously, the forum has been going for about ten years. Some people register and never post, some people post once and never again, some people post for while then move on, we hope because they are well or at least need no further help, some rarely or never post but are often in chat, and so on.
A few of the registrations were simply to try to push products so they get banned and a very few people every now and then, lose their posting rights because they don't appreciate the forum posting guidelines.