I would argue it is mostly to deter other news sites. You have done all the work finding this news and then someone else can just come along and write another a

I would argue it is mostly to deter other news sites. You have done all the work finding this news and then someone else can just come along and write another article based on what you found? You don't want that. But yes the ones "suffering" are the few readers that want to verify the contents.