I don't think that's quite right. In Lewis's thesis, you only really encounter the in/out question by interacting with people who are in. By your definition, interacting on HN puts you in already. And "and have participated semi-regularly in discussions without getting banned" is a much lower bar than anything Lewis is talking about. You'd have a much better point w.r.t. lobste.rs or other invite-only forums, but the whole concept is dubious without private discussions.