I have no business arguing with you on the topic, but I'm just wondering: is it really so that accusing someone's argument in ad hominem is ad hominem? Or have you just used "tu quoque"?
That the person's who wrote the article above thinks that the author of the other piece is flawed, isn't central to the majority of their argument. Thus using that the person who wrote the article thinks that way, as a reason to dismiss the entirety of their piece, probably qualifies as AH.