I get it, development is a craft, it's easy to judge the quality or experience level of a coworker after having to deal with their PRs for a month or two. However, it's not like any toy project I could throw on github is going to have real relation to the actual work I do, and trying to replicate e.g. some of the third party integrations I've written internally as public stand-alone packages is going to get me fired and sued by an overprotective employer.
This isn't a hypothetical fear either, multiple times I've gone through phone interviews to a "lets review some of your past work" stage, and my "I can't legally show you any of these things, but here's general descriptions of some of the major internal projects I've led or handled solo" has resulted in failing to make the next interview round.
Heck, even reasonably good software can produce a very negative impression. Utilitarian code can be seen as ugly or overly simplistic. Elegant conceptual stuff often runs the risk of grinding against biases and preconceptions of the particular reviewer.
For your second argument, I know what you mean, but that's also totally subjective, dictated by chance, and would apply equally across the board for all candidates. Even if that happens, it sort of naturally levels itself out competition-wise.
Also, remember that you're evaluating the employer too - do you want to work for someone who chooses employees that way? Would you want to work with someone who has a closed mind and an axe to grind about certain concepts? I wouldn't trust people like that to make good decisions that will make the company succeed, thereby keeping me employed - let alone providing opportunities to advance. Plus they sound like they'd be a pain in the ass to work with.
That would be difficult for people who work for companies that claim presumptive ownership over everything they produce.
I was commenting less on the article and more on the general disdain for bootcamp grads that seems to crop up in every article or thread about them. It always devolves into whether people with this education or that education are any good, and it's just completely irrelevant.
Just show me what you've done. Send me repo links, production code, or even just the end result with some sort of proof that you actually built it. That's the best part about any craft - practicing or building something creates tangible results. If you don't already have a portfolio, get to work on that before you start applying.