I do agree that one persons success with something (getting a job, losing weight etc) isn't a very good prediction on most people's result using the same technique. And yes, I don't think all aspiring developers should do a bootcamp either. It wont replace a CS degree, and there are tons of ways to become a developers just using online tools/courses.
My motive with this article isn't to encourage more people to go to bootcamps, but help those who want to go do bootcamps do better research before they apply, as there are a lot of bad bootcamps out there.
Given the lack of web developers and demand for the skill, I don't doubt that some schools have 90 percent hiring rate.