and it's ad hominem ARGUMENT (technically "argumentum ad personam").

In order for there to be an ad hominem reply, there must be a HOMINEM responded to with a derisive personal comment.

Had I said, "Joe Smoe, YOU have only a double-digit IQ," THAT would qualify.
Since I SPECIFICALLY stated:

1. Rick, I disagree.
2. RIck, I understood what you said the first time
AND THEN
3. I said, it would not be recommended for ANYONE with a double digit IQ (as in anyone ELSE as in 3rd parties).

I suspect this is just a matter (at least in part) of whose "ox has been gored" and some folks taking it personally.