This is because the platforms deincentivize posts that link to the original source by pushing them lower in the algorithm. Because the best way would be to put

This is because the platforms deincentivize posts that link to the original source by pushing them lower in the algorithm. Because the best way would be to put the content on the official pages and post the link (+ relevant excerpt) to social media. But that takes engagement away from the sites and they hate that.