Here's why: I've taken English courses and Music theory courses, but I am not a writer or a composer by any sense of the word. Sure, I can write a blog post or a comment, and I know how to compose a harmony, but I still lack the sort of knowledge necessary to fully embody the full enormity of these titles. Great composers and writers aren't always necessarily thinking "theoretically, I should do X given that I have Y." But a musician that lacks sufficient knowledge regarding music theory will generally lack the ability to compose truly great works.
Yes, most web applications can be completed by just about anyone if you train them a couple of months. But generally that's all that person is capable of. They won't be able to evaluate a technology critically because they fundamentally do not understand how or why it works. I can also create a movie script -- that doesn't mean it will be any good!
From my point of view, the non-hacker community doesn't understand that software and technology can be as aesthetically beautiful as the Sistine chapel. It takes real craftsmanship and deep theoretical knowledge to get there; you can't just wake up and produce that.
I'd like to thank the other commenters who pointed out that there are a lot of Bootcamp grads who did attend college -- I had no idea. It would be interesting to see the actual stats on that.
(Of course I acknowledge a college degree doesn't necessarily imply the level of craftsmanship I'm talking about here, but generally the theoretical knowledge obtained coupled with working in a meaningful way lead to this sort of craftsmanship. Also, just as art is subjective, beautiful software is as well.)