Because that's largely what boot camps focus on. They are there to teach you what's popular right now, which is web dev. They aren't going to teach you kernel development, or backend application development, or graphics skills, because that's not what 'omgstartups' are hiring for.
Exactly. Not to mention "not hip" things like security, performance sensitive code, distributed systems, HCI, solid understanding of computing theory, and so on.
Web devs tend to be easily replaceable, so why not hire a bunch of juniors (at a cheap cost) to get the job done? This is what it seems these types of "academies" are targeting anyway. Like "timr" said in this thread: "... a commodity product for a commodity world."
Fair enough, but I don't see how any of this has to do with the topic at hand, which was boot camps are for suckers. I wouldn't consider the junior developers who are working out well in the parents reply suckers - sounds like they're employed and working out well.
They bought a product (bootcamp) in the pursuit of a career in software engineering. Odds are they aren't equipped for more than a series of jobs doing webdev scut work.
"Suckers" might be a bit strong, but their expectations may suffer a certain misalignment with reality.
I know web devs who have taught themselves CS fundamentals and the stuff you mentioned, but they started with boot camp doing Rails. And why not? They were able to teach themselves this stuff while working for a good salary and getting experience for their resume.