While the bloggers are accepted by someone at `forbes.com`, the blogs themselves are left largely without editorial oversight. The opinions are purely the blogger's own. So long as the blogger brings in clicks (which determines their pay) and doesn't cause problems for Forbes, then they are practically left to their own devices.
Therefore there is a big difference in assumed quality between the two. There is of course no reason why a blogger can't write quality content but it's no more "Forbes" than any given Medium blogger is.
I'm more than happy for Forbes to get blow back for using a blogging network to drive up their site traffic. However, when submitting or upvoting `forbes.com/sites` blog posts on HN it would be great if people thought more about whether it's really a worthwhile read. Don't be taken in by the Forbes name and do realise the blogger is being paid for clicks.
It would be great if HN could highlight `/sites` in some way but I think it currently can only show the domain.