First of all that is not my forum and I don't know why you assumed that.
I did a google search for the topic I was looking for and I came up with both forums. Informing someone they are copying another persons post is the right thing to do.
The well-researched post that the original poster created, sited clinical studies just like any research paper or document might do.
The issue is not with the citations that the original author used to draw his conclusion, but the context in the way it was written. Authors who use reference material either as inline quotes, citations, bibliographies, etc. are not claiming first rights to their source material (this is in fact why they site their sources) but the context in the way the research paper or article was written.
Quoted or sited research articles written for the internet are automatically copyrighted and belong to the original (1st) author the moment the article(s) are posted publicly by that original author. As per your request, I read your TOS and Blowdry's post is in violation of it.
Since your member Blowdry copied a research article verbatim from the original author (the automatic copyright holder) without proper credit to the original author, that constitutes plagiarism and copyright infringement.
If you were in a university writing a research paper and the guy next to you wrote his on the same topic using some of the same source material there would be no issue with that. However if you photo copied his paper exactly the way he wrote it and turned it in with your name on it, that is stealing some other's work.
The poster Blowdry, clearly and blatantly copied verbatim the original authors researched forum post. Quite frankly I'm taken back by the fact that you were unable to see this logically when it is so blatantly obvious.
The fact that you deleted the link to the original authors work so that person can not get proper credit is very troubling. It just proves to everyone that you support this type of plagiarism on your forum and demonstrates your lack of integrity.