"Conflict of Interest: Where a source seeks to convince by a claim of authority or by personal observation, identification of conflicts of interest are not ad hominem – it is generally well accepted that an "authority" needs to be objective and impartial, and that an audience can only evaluate information from a source if they know about conflicts of interest that may affect the objectivity of the source. Identification of a conflict of interest is appropriate, and concealment of a conflict of interest is a problem."
To be fair though, the author does not hide any conflict of interest - it is stated in the footer - and the argument is made with evidence, not simply "I've been a doctor for 25 years, listen to me!".
This is coming dangerously close to dismissing all arguments from experts because their expertise has made them "biased" or presents a "conflict".
There was just an article on the front page not too long ago about the misuse of logical fallacies, so thanks for correcting that for everybody. As a rule of thumb, an 'Ad hominem' is only fallacious when the 'attack' is irrelevant to the argument; probable motivation to exhibit bias is not irrelevant to the argument.
"Conflict of Interest: Where a source seeks to convince by a claim of authority or by personal observation, identification of conflicts of interest are not ad hominem – it is generally well accepted that an "authority" needs to be objective and impartial, and that an audience can only evaluate information from a source if they know about conflicts of interest that may affect the objectivity of the source. Identification of a conflict of interest is appropriate, and concealment of a conflict of interest is a problem."