Not all insults are ad hominem. For this to be ad hominem, he would have to be saying that the reason Attwood was wrong was because he "gets off on making beginners feel like they're worthless..."

Here's a quick illustration:

Ad Hominem: Jeff Attwood gets off on being an ass. Therefore he is wrong.

Not Ad Hominem: Jeff Attwood gets off on being an ass. Incidentally, he is also wrong.

Technically you may be right, if one is in a debate club perhaps. In a real world debate the close position of two elements, especially when one is composed of emotional content, draws a strong implied link between the two points even if they are separate. It's not a compelling defense to say that everyone should be an expert at logical debate and should know to ignore the insults one heaps on one's opponents.

You need to learn the difference between insults and logical fallacies. This has nothing to do with whether or not insults are bad in a discussion (they almost always are), it has to do with the poster citing the ad hominem fallacy incorrectly because they think using Latin words will strengthen their point.

We should start a movement to persuade everyone to learn logical fallacies. Then we'll get some other guy begging everyone to stop following the fad and not learn logical fallacies. After that, we'll get a third guy writing a response saying the other guy is wrong. Finally, we'll get a lot of people illogically applying logical fallacies, and we'll get them then!

Seriously, understanding of logical fallacies seems to be in very short supply around HN. If I didn't know any better I would think I'm over at Reddit.

Ad hominem (argumentum ad hominem) is a specific term of art to describe arguments that try to counter a thesis by attacking the character, qualifications, standing etc of the person claiming the thesis.

It does not mean an argument in which a person insults the person claiming the thesis. Insults rarely add anything to an argument but that is a different matter.

Also note that an ad hominem doesn't need to be insulting - it could be a very polite statement such as "This argument is incorrect because Mr Atwood is unqualified to discuss matters of education as he is not himself an educator". This is not really insulting (though I would argue that Jeff is in a way an educator) but is still an ad hominem.