I'm a designer / developer yes

Everyone in the world hates spam, so using your example of spec work is like spam, everyone should hate spec work as it is full of crap and needs to be rid off
Dodgy street sellers, loan sharks, all the examples you give are "dodgy"/illegal/should be wiped out, so yes I agree with you there, spec work should be wiped out. Nice way to compare it to illegal/damaging things though, I see it in that exact way myself
If there was no spec work websites then people would understand that web design is not free and takes 20 minutes to do, its a million if not billion dollar industry that doesn't need these things holding it back or damaging it by allowing anyone to become a designer. Ever had a client who starts giving you design advice? Thats because they think they can design because everyone these days does, and spec work is promoting this as it allows anyone to download an illegal copy of Adobe CS4, whack it open, make some crap and hey, they're a designer, not!
Some great reads here if you feel strongly on the debate for spec work, no idea why anyone really would!
http://www.37signals.com/svn/posts/1253-the-nospec-campaign-vs-crowdspring
http://www.no-spec.com/
Oh and every bit of shoddy design doesn't do me a great service, as people come to me uninformed asking for an entire website for £300 or try offering me advice on how to do my job which is just ridiculous as you wouldn't offer a trained mechanic advice just because you bought a car would you? Its just ridiculous in every sense!