Well, perhaps because none of use who know how to write an importer use MySpace?
Does MySpace have any way to export full content (comments included would be nice)? If not, then you will likely have to resort to the cut and paste approach. If there’s no way to get the content, then there’s no way to import it.
So, be frustrated all you like, but you’re not getting support because you’re asking for something that does not actually exist.
Edit: There are tools to create full RSS feeds for MySpace blogs online. Google found this one for me: https://makedatamakesense.com/myspace/ . You could use these to make RSS feeds and then import that. Won’t get comments though. Can’t do that until MySpace actually has an API and a way to download comments and all the associated information.