I doubt they paid a fee. But clearly, they're either gaming the system or there's a very large population on HN who are trying to break into the industry with no credentials.
But as many few people will dispute that you can get started writing production code much faster in the latter.
And what I will add, is that they'll be an average 80% as good as their fresh out of uni CS peers, if not more.
To me it is the difference between learning to build and learning to design (something to build).
Not necessarily "clearly"; perhaps it's another thing altogether. We tend to be anti-marketing, and many see coding schools as selling a dream ("99% of our graduates get hired at a $100K starting salary"), while producing graduates that are ready to be interns at best. The idea of the anti-bootcamp, in the sense that it's not profit-driven, resonates.
I'm curious what kind of credentials you're referring to, however. Paid boot camps? CS degree?