"If I was the sort of person who took umbrage at post hominum attacks"
Post hominum? What the hell is that? There is no such term use logical discourse.
Maybe you meant "ad hominem".
I recommend checking up what ad hominem means. Ad hominem is a personal attack (on character, motive) on the person making an argument.
My criticism was not a personal attack by general description of certain type of behavior encountered with people posting similar responses. It directly reflects to the subject (content of your comment-criticism), so it is not diversion from the subject - an attempt of rebuttal of the argument by using logical fallacy.
Your misuse/accusation of ad hominem can be actually possibly treated as logical fallacy itself (red herring) - an attempt to change the subject by of unsubstantiated accusation of logical fallacy.