How is this different from GET arguments in the URL? I mean is this relates only to URL fragment, because javascript can parse URL parameters as well and any spam site can abuse it even with rewrite in the path part in the URL.
I haven't tested that but I think it's possible to modify the fragment with Javascript: https://stackoverflow.com/a/4282075
So my idea would be getting looo.ong to create a special client-side redirection webpage that would remove the fragment part using Javascript before performing the redirection with Javascript. And no. Using HTTP redirection response on server side won't work.
EDIT: I've actually seen URL redirection websites that removes the fragment part so it should be doable. Perhaps the purpose of that is to avoid spam abuse.
Yes, this is how single-page apps allowed linking to subpages before history.pushState existed.