There has been no 'U turn'.
The experts have not 'changed their minds'.
Guidance on solids - which was never intended to apply to every individual anyway - has not changed and will not do so in the light of this current article.
It's not a study. It's not new research. There is no need for anyone to feel relieved, smug, angry, or frustrated.
Of course things change as new knowledge and new research is assessed - we'd want all knowledge and research assessed, I think, and set into context, and evaluated for validity etc etc, before changing guidance.
This article is suggesting investigation of further studies.
It's not telling anyone what they did was wrong, or right. It's actually not 'telling' anything. It's an academic opinion piece, in professional journal, aimed at professionals. Happily, we can read it for ourselves, too. I wish people would do this instead of reading headlines only.