....first I must admit that I only skimmed the article.
On the site I use to count calories you get to eat more when you exercise. A lot of people get confused by this (you know,
why the heck did I just burn all these calories if I'm just eating them back?!?) because it keeps you at a certain deficit. The whole 500 calories a day equals one pound a week, if you burn 200 that makes it 700, etc. The only problem with this is, of course, overestimating how many calories you've burned. But I lost 57 pounds exercising (and challenging myself with it) about 5 to 6 days a week and eating my exercise calories. And most weeks when I was correctly on plan I lost my targeted one pound a week. (Granted, there were many weeks I wasn't on plan at all and either didn't lose or maintained, and after a year of not keeping up with calories I'm back up several pounds. But that was all my own fault.)
So I think the issue isn't so much exercise can't "make you thin" but that it absolutely MUST be coupled with careful and healthful eating. And if the focus is on being a fit and healthy person and not just "thin" then exercise has to be incorporated into the mix, in my opinion.