That's not critical thinking though, it's fallacious thinking. Whether or not someone is a "thought leader" has no bearing on the quality of the article.
An "appeal to authority" means something more specific (e.g. the logical fallacy "argument from authority") and this is not happening here.
The whole point I'm trying to make is that we should evaluate the writing based on its content. The person I originally responded to was dismissing it solely because of the person who wrote it (which ironically an ad hominem is a fallacy very similar to an appeal to authority but for the opposite reason).