Also, you must not have read the article because the second paragraph describes subjecting them to regular fasting regimes, not lifelong caloric deficit. I don't believe lifelong caloric deficit is even possible nor is it mentioned in the article. 

Lastly, you can gain muscle and then maintain it on a caloric deficit anyways, it's what body builders do every season. So even your initial assertion is wrong. Now I know that is a little different, but you can build muscle and not gain weight too. I feel like you're way over simplifying the process of muscle gain and retention and the essence of this article is that obesity is bad