I have a limited amount of time in my life and no wish to spend it playing "spot the logical fallacy in every paragraph" with McArdle. I have found it more efficient to learn that she is a feckless human being who will lie (by omission and otherwise) and entirely ignore her than teasing out the truth in her writings, which would require reading in detail the primary sources she is allegedly summarizing as well as the ones she silently omits.
Calling ad hominem is well and good and something to keep in the back of your mind, but I tend to agree with Daniel Davies that "giving known liars the benefit of the doubt" is more likely to steer you wrong.