Yes. See response to author's comment below.
On vitamin C - I stated dietary vitamin C to make it clear I was not referring to supplemental vitamin C. I was hoping to avoid this exact rabbit hole; that example was just to highlight an issue with the argumentation.
> It is an essential hormone, definitely, but not a magical pill that will ward off disease. There are conditions that benefit from Vitamin D supplementation - for hypoparathyroidism, a condition that can cause dangerously low calcium levels, Vitamin D is lifesaving. For otherwise healthy adults, the benefit is less clear.
Takeaways: it's not clear what preventative benefits it has.
Even to use your vitamin C example, it's also widely touted to take vitamin C for general well being, such as helping colds. But its preventative benefits aren't clear [1]. Nobody has ever said vitamin C is useless, but it's just not a panacea (much like the article claims about vitamin D).
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1160577/