Oh, I agree. I think this other Wikipedia article, though, points a finer picture on what it means to be an independent contractor (which is a legal term for tax purposes and doesn't really have a lot to do, as you say, with how you actually structure your work).
http://en.wikipedia.org/wiki/Independent_contractor
I'd argue that in most instances the 1099 jobs on Gaswork are being advertised as independent contractor type positions where one is to "show up, we'll give you work, but don't expect to become a partner" type deal. Now, there may be exceptions to this, but overall I think the idea behind the 1099 listing is that it's basically a fend for yourself (at least in the insurance and benefits area) type arrangement. And, being paid through a 1099 has a lot of specific tax and legal ramifications.
Still, not disagreeing with everything else you said. Especially the part about having the balls to negotiate yourself a good contract or walking away.
-copro