> Uh, the publicly-edited, well-sourced, and very thorough Sourcewatch wiki article isn't even in the same galaxy as "ad hominem".

http://en.wikipedia.org/wiki/Ad_hominem

An ad hominem (Latin: "to the man"), also known as argumentum ad hominem, is an attempt to link the validity of a premise to a characteristic or belief of the person advocating the premise.

The suggestion was that something from cato was bad because its supporters were bad, which is ad hominem. The accuracy of the list doesn't change that.