Sue 4chan and members? And garner the focused attention of one of the most vile communities of trolls the world has ever seen? Let me get my popcorn, because that will be an epic shitshow to watch.
Users that bought a 4chan pass could be considered "members" of a sort. Regardless of whatever you choose to call them, be it "users", "members", or "shitposters", I think the point you're trying to make is overly pedantic.