Ad hom would be saying the author smells like moldy cheese and therefore we should disregard his opinion.
The parent comment is not using ad hom. They're critiquing the author's work and assessing their credibility based off of that. It's perfectly fine, and a great viewpoint to consider.
The parent comment is not using ad hom. They're critiquing the author's work and assessing their credibility based off of that. It's perfectly fine, and a great viewpoint to consider.