I think you're reading into the question a bit much - it's just asking "What's the best city for Devs without a Degree?" Granted, having a why is really nice. So here goes:
I'm not sure I agree with OP's assessment that it's be best without explanation, as a Portlander myself. There really aren't that many tech jobs here, not like SF at least, and given that it's competitive (everyone wants to live here), anyone who wants to see a C.S. degree on their resumes can discard the others until they find what they're looking for. Granted, since a lot of companies here are small and don't have the money to fly prospective hires in for a visit, living here and at least having technical skills is valuable. It also helps your case that aside from Intel we don't have much of a presence from top software giants - ya know, the kinda that can be picky about who they hire. A lot of the jobs here aren't "high tech" though - as a developer you might have a hard time finding the sweet spot of fun/interesting/world changing work you're looking for.
That said, the DIY ethos is strong here, and there really aren't that many techies, so a good history of development will get you as far here as anywhere. I think the lack of nearby schools producing C.S. grads is another factor in why most of our tech community is self-taught or imported from somewhere where C.S. is taught.
Culturally, I think casual tech people are happier here since the community is small and not as serious as in SF or other places. People who are really serious about their work are rare and talking about work makes you seem clueless in a city full of people who love to play.
