…Which they are, of course: just not to HuffPo. Which is why that the “strike” that some of them are invoking because they aren’t getting paid for their freely-provided content is so… well, it’s kind of cute. Diagnostic of a sad mass delusion of the relative worth of their provided free content, when contrasted against the difficulty in acquiring new free content of equal or greater value, but cute.
More seriously, when you have a site of HuffPo’s size, then you will get people who are happy to trade free content in exchange for free publicity. Some of those people will be good enough at what they do to be usable. You cannot compete with those people unless you first accept that they are in fact being compensated for their work, and adjust your pitch accordingly. Just the way it goes, folks.