Scribble Hub is for Original Works only right?
You can post
your translations on Scribblehub, but they won't be searchable in any way, nor will they be visible in the front page. They'll mostly be hidden from the main site and only accessible via direct links (mostly through the Novelupdates page in particular, Scribblehub's sister site.).
If you see a translation in the front page, you can safely report it, and Tony (the owner of both sites) will make the translation hidden and only accessible through direct links.
Why are there people posting up to 394 chapters of some Qidian Webnovel machine translation here and still allowed? Correct me if I wrong, but isn't this against the rules?
If they are posting stuff that has been translated by someone else, then they are stealing the translation. Report it so that it can be taken down.