For me, "Shadowbanning" or "hellbanning" means that the post of the user/site are [dead] but the systems lies to the user and to nim/her show the post as alive. And the only way to notice is to logout or get another computer and check the post from there.
Killing the post form an user or site automatically, and showing to the user that the posts are [dead] is not shadowbanning. I call it "autokilling" but I'm not sure that it is he official name.
Almost all the recent case/discussions of similar cases were simply autokilling. In the initial times of HN it was more common to have hellbanned users, but it's very rare now. Moreover, I remember a comment of dang where he said that they were considering to remove all the hellbanning and only use autokilling. I'm not sure if they finally made that change.