I generally agree with what you're saying, and it's amusing how she proceeds to do something that is essentially what she is criticizing Gladwell for doing himself, but I give benefit of the doubt to the critic, because there is a remarkable difference in medium. It's a book review, not a complete refutation. She has about a dozen paragraphs to summarize and critique 300+ pages. Is there enough space to complete address even one of the cases brought up in the book? I think not.
I've read the book. It's entertaining, but I don't think it's as well-developed as Blink or The Tipping Point. I think Gladwell is a good writer who serves a previously unfilled role as a popular popularizer of academic work. However, every time I read his work, I wish that experts of the fields he reports on would also write popular expositions that could be consumed by an audience like that of the New Yorker.
I know that the evidence backing some of what I was reading was sketchy at best. Asian children score higher on math tests because their ancestors labored in rice fields? Please. It doesn't detract from the entertainment value of the book, but I would think twice before believing what I read in the book was indicative of reality.
As for your theory argument, I would have to disagree in many different cases. Suppose that you only chose to include data points that support your argument. Then people have every right to pick an alternate data point, claim that your study is faulty and that you're being irresponsible. This is exactly what many of his detractors are pointing out, and it is a point that is often missed.
The primary argument against the book and the Gladwell style of investigation is that he tends not to include or even discuss studies or points or examples that do not support his argument. This is understandable, since he is attempt to speak to a popular audience and does not have the space to discuss every relevant study if he wants to run through all of his cases, but by doing this, he makes many smart people feel like he is trying to pull the wool over their eyes.