Why do news sources not link to fulltext articles?

“Journalists from newspapers and other news gathering agencies often do not provide direct links (or even a full citation) to the research being discussed.  Journalists and news agencies know that most readers will not be able to access the fulltext of the article because of subscription fees or other limitations on access. This can be frustrating for general readers who wish to read the source article, but those who are affiliated with an academic institution can often find the source article from the publisher.  In addition to the version of the article at the publisher, a freely available version may be findable in an article repository. For example, this astronomy post at ScienceNews wrote ‘But the new simulation, described online June 20 in Nature, suggests that a stellar signature exists in the form of fluctuating radio waves, oscillations produced when young stars and nascent galaxies warm and excite surrounding hydrogen gas.’  The next paragraph mentioned co-author Eli Visbal.  From this information, I searched for the word ‘Visbal’ on the website of Nature to find the article, ‘The Signature of the First Stars in Atomic Hydrogen at Redshift 20.’ This article is only available to subscribers of the journal, or one might be able to pay the publisher for access to it. In this case, a reader who is not affiliated with an institution that subscribes to Nature would have to pay $32 to download the one article.  If a news organization provided a direct link to the article, they know that many readers would be put off by the request for a credit card to read the article. However, many scholars and researchers legally post reprints (or preprints) of their articles in a variety of archives.  In this case, the authors posted a preprint entitled ‘The Grand Cosmic Web of the First Stars’ at the Cornell University eprint arXiv. Even though the title of the article and the abstract are different from the Nature version, the five authors are the same and listed in the same order, much of the text of the two articles are the same, the dates of submission and revision are the same, and the figures are the same or very similar. Thus, I concluded that ‘The Grand Cosmic Web of the First Stars’ is the freely available preprint of the official Nature article.”