In what way could it be ad hominem? Where did I attack the poster? I did make an assumption of why they were arguing against it in such strong terms, but how does an assumption make for a personal insult on the author?
I realize they also brought up points about why they thought this was bad. The rest of my comment was spent replying to those points.
No, it obviously doesn't underlie their criticism ... and that claim is ad hominem.
I think there are numerous reasons why Clippy is a poor choice for a mascot, and your correspondent presented some of those reasons.