You just have to read the Article. It's stated in the 2nd paragraph why. Basic defense of liberty of speech was why.
"Erna Solberg, the Conservative prime minister, called on Facebook to “review its editing policy” after it deleted her post voicing support for a Norwegian newspaper that had fallen foul of the social media giant’s guidelines."
"Erna Solberg, the Conservative prime minister, called on Facebook to “review its editing policy” after it deleted her post voicing support for a Norwegian newspaper that had fallen foul of the social media giant’s guidelines."